Building a N/A 5.3 (First Swap)
03-19-2018, 10:34 PM
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Building a N/A 5.3 (First Swap) Okay so I'm doing my first swap (5.3 into an 06 Colorado Xtreme) and my goal is to make a bit over 400hp at the rear wheels N/A.
- 2000 5.3 LM7 (currently with 862 casting heads)
- Crane Cams 224/232 Cam w/ springs (https://www.summitracing.com/int/par...9121/overview/)
- Speed Engineering Long Tube Headers (https://www.speed-engineering.com/sp...1999-2006.html)
My question is for the cam I want to use I need 11:1 compression ratio and stock the LM7 makes 9.5:1. What is the best and safest avenue for me to increase the compression to what is required ? I spoke to a friend about swapping the heads and he said 706 casting heads should get me close but everything I read says the 862's and 706 are identical.
I'm sure this is a common question, could anyone offer me some help and possibly an avenue that I could teach myself how this all works ?
Thanks!
- 2000 5.3 LM7 (currently with 862 casting heads)
- Crane Cams 224/232 Cam w/ springs (https://www.summitracing.com/int/par...9121/overview/)
- Speed Engineering Long Tube Headers (https://www.speed-engineering.com/sp...1999-2006.html)
My question is for the cam I want to use I need 11:1 compression ratio and stock the LM7 makes 9.5:1. What is the best and safest avenue for me to increase the compression to what is required ? I spoke to a friend about swapping the heads and he said 706 casting heads should get me close but everything I read says the 862's and 706 are identical.
I'm sure this is a common question, could anyone offer me some help and possibly an avenue that I could teach myself how this all works ?
Thanks!
03-20-2018, 01:12 AM
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https://www.google.ca/amp/www.hotrod.com/articles/ls-cam-test-comparison/amp/
That's the link to the cam tests they did. Like I said I'm completely new to all of this and trying to do my research to learn. In the article they make it sound like it's basically a drop in cam with spring upgrades required but then going to summits page they say it requires an 11:1.
How much would have to be milled to make an 11:1 CR? Is that even safe to do or would I be running into piston clearance issues?
Is there a better way to make my goals with a different cam setup
That's the link to the cam tests they did. Like I said I'm completely new to all of this and trying to do my research to learn. In the article they make it sound like it's basically a drop in cam with spring upgrades required but then going to summits page they say it requires an 11:1.
How much would have to be milled to make an 11:1 CR? Is that even safe to do or would I be running into piston clearance issues?
Is there a better way to make my goals with a different cam setup
03-20-2018, 09:24 AM
#5
You dont have to have 11:1. When they say you need high compression its because usually a larger duration cam will be a little lazy especially on low end if you have low compression.
I would just run the cam as is honestly. Its not going to hurt anything and will run fine. If you are happy with the way it runs thats all that matters.
I would just run the cam as is honestly. Its not going to hurt anything and will run fine. If you are happy with the way it runs thats all that matters.
03-20-2018, 11:39 AM
#6
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862 and 706 castings have identical chambers.
Flattop pistons with the existing 862 heads will get you to 10.5:1. A .040 Cometic gasket will raise compression a tick more. I'd have the 862s ported and look at a few different offerings outside of Summit for a camshaft.
What intake are you planning on using?
Flattop pistons with the existing 862 heads will get you to 10.5:1. A .040 Cometic gasket will raise compression a tick more. I'd have the 862s ported and look at a few different offerings outside of Summit for a camshaft.
What intake are you planning on using?
03-20-2018, 08:21 PM
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I'm going to stay in stock form intake for now (5.3 truck intake) as I've heard they aren't bad. Eventually I'd like to use the TBSS intake down the road.
What other cams would you recommend ? Would the cam I have selected be terrible in the low RPM range ?
What other cams would you recommend ? Would the cam I have selected be terrible in the low RPM range ?
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03-21-2018, 08:32 AM
#8
TECH Fanatic
The thing to remember is that the advertised RPM range of a camshaft is dependent upon the engine's displacement, as well as other variables. So, if the given powerband of a camshaft is based off a 5.7 or 6.0, the powerband for your 5.3 will start a touch higher. You have to remember that the engine as a whole is a system, and the camshaft is just one component of that system. It needs to work with the other parts in order to function, and you should keep those other parts in mind when selecting a different camshaft. In your case, you will be using 862 heads and a long runner intake manifold.
The 862 heads have small chambers, but they also have smaller ports and smaller valves than other cathedral heads. One thing you can do to improve the heads is have them machined to accept factory 2.00 intake valves. This will improve flow and shouldn't break the bank to have done. You could also step up to a 2.02 intake/ 1.57 exhaust at a higher expense, but at that point, you'd be going deeper down the rabbit hole and it wouldn't be worth the effort without adding in some portwork.
Regardless of whether you choose the LM7 or TBSS intake, you have to remember that they both have longer runners than their car counterparts and are designed with lowend torque in mind. So, pairing this intake with a camshaft designed to operate higher in the RPM band isn't going to provide the most desirable outcome because by the time the camshaft is getting started, the intake is running out of breath.
Most importantly is your goal with this truck. From what I've gathered, you just want something that is fun to romp on while cruising around on the street. Don't concern yourself with achieving a number so much as with achieving a strong performer that drives well. Hitting a number is no fun when the thing is bucking and surging at lower RPMs.
The other keys to your camshaft selection are your transmission and gearing. Are you using an auto or manual? If auto, you can make up some loss in lowend torque with a higher stall converter to ensure that the engine stays within its powerband. If a manual, you can play with the rear gear ratio to mitigate the same issue.
Personally, with upgrading the intake valves, I'd be looking at something in the low 220 range with a 4-6* split between the intake and exhaust and keeping the lift at or under .600". Something like Cam Motion's Titan 2 LS1 cam (221/226, .595", .586", 112+2). If you just want to leave the heads alone, I'd look more at the Stage 3 LS1 cam from Cam Motion (218/224, .553, .553 -116+3).
You could also call Cam Motion and they would be able to drum up some custom specs for you.
The 862 heads have small chambers, but they also have smaller ports and smaller valves than other cathedral heads. One thing you can do to improve the heads is have them machined to accept factory 2.00 intake valves. This will improve flow and shouldn't break the bank to have done. You could also step up to a 2.02 intake/ 1.57 exhaust at a higher expense, but at that point, you'd be going deeper down the rabbit hole and it wouldn't be worth the effort without adding in some portwork.
Regardless of whether you choose the LM7 or TBSS intake, you have to remember that they both have longer runners than their car counterparts and are designed with lowend torque in mind. So, pairing this intake with a camshaft designed to operate higher in the RPM band isn't going to provide the most desirable outcome because by the time the camshaft is getting started, the intake is running out of breath.
Most importantly is your goal with this truck. From what I've gathered, you just want something that is fun to romp on while cruising around on the street. Don't concern yourself with achieving a number so much as with achieving a strong performer that drives well. Hitting a number is no fun when the thing is bucking and surging at lower RPMs.
The other keys to your camshaft selection are your transmission and gearing. Are you using an auto or manual? If auto, you can make up some loss in lowend torque with a higher stall converter to ensure that the engine stays within its powerband. If a manual, you can play with the rear gear ratio to mitigate the same issue.
Personally, with upgrading the intake valves, I'd be looking at something in the low 220 range with a 4-6* split between the intake and exhaust and keeping the lift at or under .600". Something like Cam Motion's Titan 2 LS1 cam (221/226, .595", .586", 112+2). If you just want to leave the heads alone, I'd look more at the Stage 3 LS1 cam from Cam Motion (218/224, .553, .553 -116+3).
You could also call Cam Motion and they would be able to drum up some custom specs for you.
03-23-2018, 11:13 PM
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Thanks a tonne for all the explanations man.
You are right in the assumption that the goal for the truck is to just have a fun summer driver that I can get on from time to time and take to a track day for ***** here and there. I think I would prefer the truck to be torque-y (assuming I can put that power down on a 275 rear tire possibly with traction bars).
The truck will be a manual trans which is another hurdle I've been trying to overcome as I'd like to get a t56 into it but with the finances how they are it will more than likely be an nv3500 from an s10 this year and be upgraded next year. (gearing in an nv3500 is not optimal and I'd like to build the truck with the idea in mind that it will be getting a t56 or tko for the following summer).
Sorry for sounding stupid here, you are saying to have the 862's machined for larger intake valves. This is just to allow more air into the chamber faster ? Would this increase compression? If I did this in addition to decking the heads back a bit would that be ideal ?
In regards to the cam I look at the numbers and try to get a hold as to what they all mean. What the a larger vs smaller difference in the intake and exhaust duration change (ie. 218/224 vs 224/232)? I'd like to have a cam that is a little "lope-y" and as the vehicle is going to likely be staying naturally aspirated I'd like to get as much gain from the cam and changes to the heads as possible while obviously keeping the truck strong throughout the rev range. (if anything id like to have low end torque and strong power through the mid range ... what does this look like in the way of the cam?)
You are right in the assumption that the goal for the truck is to just have a fun summer driver that I can get on from time to time and take to a track day for ***** here and there. I think I would prefer the truck to be torque-y (assuming I can put that power down on a 275 rear tire possibly with traction bars).
The truck will be a manual trans which is another hurdle I've been trying to overcome as I'd like to get a t56 into it but with the finances how they are it will more than likely be an nv3500 from an s10 this year and be upgraded next year. (gearing in an nv3500 is not optimal and I'd like to build the truck with the idea in mind that it will be getting a t56 or tko for the following summer).
Sorry for sounding stupid here, you are saying to have the 862's machined for larger intake valves. This is just to allow more air into the chamber faster ? Would this increase compression? If I did this in addition to decking the heads back a bit would that be ideal ?
In regards to the cam I look at the numbers and try to get a hold as to what they all mean. What the a larger vs smaller difference in the intake and exhaust duration change (ie. 218/224 vs 224/232)? I'd like to have a cam that is a little "lope-y" and as the vehicle is going to likely be staying naturally aspirated I'd like to get as much gain from the cam and changes to the heads as possible while obviously keeping the truck strong throughout the rev range. (if anything id like to have low end torque and strong power through the mid range ... what does this look like in the way of the cam?)
03-25-2018, 07:50 PM
#10
The "more" cam you put in, the more you give up any kind of low-RPM performance.
"Big" cam #s move the whole power band UP in the RPM range. Problem then is, if the converter gears and driver needs keep the thing in the low RPM range, you can end up with a "big HP number" car that is a TOTAL DOG for the purpose you want it for. One of those things that'll wind up FOREVER but your grandma's minivan will WAX it from stoplight to stoplight.
A 218/224 cam is PLENTY big for a LM7. Too big if anything, based on your description of what you're looking for. I'd suggest checking with people that make cams for these motors, not necessarily just the big names. Check at Texas Speed, CamMotion, Vinci, Katech, there's plenty of others that specialize in these motors and don't just crank out me-too grinds that aren't specific to the needs of this kind of engine. Be HONEST about your goals and needs; just like your doctor, if you lie to them, they can't actually help you. They'll be helping the person you wish you were instead of the one you ARE.
My suggestion would be: run that cam AT MOST and maybe smaller; use the stock size valves; hand-port the heads, mostly just the angles and steps and other irregularities RIGHT IMMEDIATELY behind the valve (don't get all worked up over "port matching" type of crap), plus flow-contouring the valve guides SLIGHTLY into a "teardrop" or "airfoil" shape (remember, you are NOT trying to make the port larger, only, make the air flow through it more smoothly); a set of headers as you mention, and a good exhaust. Being a manual you don't have to worry about a converter but gears are even more important. You'll want 3.73 for sure, maybe a bit more.
You can't deck the heads very much without running into other problems. Just have em cleaned up. Put in good valve springs; doesn't seem to the n00b like a big deal, but inadequate valve springs will KILL the performance of a motor, and possibly kill other parts as well. you can get good kits here. http://www.texas-speed.com/p-6443-pa...-pac-ks13.aspx I'd suggest the KS-14 for the cam you seem to have but by all means ask them if that's the right match for what it actually is. Don't run stock push rods, but don't buy them until you have THE WHOLE REST of the motor put together and can measure for the right length. Check your rockers CAREFULLY for signs of wear, failure, etc.
The LM7 intake is fine for what you're doing. You won't really gain anything with the TBSS one. Keep your money in your pocket on that one.
Changing valve size doesn't change compression.
"Lope" is the ENEMY of low-RPM torque. Avoid the n00b trap of "sound". Choose parts that give RESULTS, not spank-off.
"Big" cam #s move the whole power band UP in the RPM range. Problem then is, if the converter gears and driver needs keep the thing in the low RPM range, you can end up with a "big HP number" car that is a TOTAL DOG for the purpose you want it for. One of those things that'll wind up FOREVER but your grandma's minivan will WAX it from stoplight to stoplight.
A 218/224 cam is PLENTY big for a LM7. Too big if anything, based on your description of what you're looking for. I'd suggest checking with people that make cams for these motors, not necessarily just the big names. Check at Texas Speed, CamMotion, Vinci, Katech, there's plenty of others that specialize in these motors and don't just crank out me-too grinds that aren't specific to the needs of this kind of engine. Be HONEST about your goals and needs; just like your doctor, if you lie to them, they can't actually help you. They'll be helping the person you wish you were instead of the one you ARE.
My suggestion would be: run that cam AT MOST and maybe smaller; use the stock size valves; hand-port the heads, mostly just the angles and steps and other irregularities RIGHT IMMEDIATELY behind the valve (don't get all worked up over "port matching" type of crap), plus flow-contouring the valve guides SLIGHTLY into a "teardrop" or "airfoil" shape (remember, you are NOT trying to make the port larger, only, make the air flow through it more smoothly); a set of headers as you mention, and a good exhaust. Being a manual you don't have to worry about a converter but gears are even more important. You'll want 3.73 for sure, maybe a bit more.
You can't deck the heads very much without running into other problems. Just have em cleaned up. Put in good valve springs; doesn't seem to the n00b like a big deal, but inadequate valve springs will KILL the performance of a motor, and possibly kill other parts as well. you can get good kits here. http://www.texas-speed.com/p-6443-pa...-pac-ks13.aspx I'd suggest the KS-14 for the cam you seem to have but by all means ask them if that's the right match for what it actually is. Don't run stock push rods, but don't buy them until you have THE WHOLE REST of the motor put together and can measure for the right length. Check your rockers CAREFULLY for signs of wear, failure, etc.
The LM7 intake is fine for what you're doing. You won't really gain anything with the TBSS one. Keep your money in your pocket on that one.
Changing valve size doesn't change compression.
"Lope" is the ENEMY of low-RPM torque. Avoid the n00b trap of "sound". Choose parts that give RESULTS, not spank-off.
03-25-2018, 10:38 PM
#11
TECH Senior Member
The "more" cam you put in, the more you give up any kind of low-RPM performance.
Check at Texas Speed, CamMotion, Vinci, Katech, there's plenty of others that specialize in these motors and don't just crank out me-too grinds that aren't specific to the needs of this kind of engine. Be honest about your goals and needs; just like your doctor, if you lie to them, they can't actually help you. They'll be helping the person you wish you were instead of the one you ARE.
Check at Texas Speed, CamMotion, Vinci, Katech, there's plenty of others that specialize in these motors and don't just crank out me-too grinds that aren't specific to the needs of this kind of engine. Be honest about your goals and needs; just like your doctor, if you lie to them, they can't actually help you. They'll be helping the person you wish you were instead of the one you ARE.
03-26-2018, 07:54 AM
#12
TECH Fanatic
This thread has a ton of information in it. Reading throught it and the links within will help you better understand camshafts specs and the math behind them. Or it will make you go cross-eyed. One of the two:
http://garage.grumpysperformance.com...pec-card.1477/
The larger LS1 valves will allow for more airflow, but they won't increase compression. To increase compression on your motor, you can mill the heads up to .030" and use a Cometic .040" gasket. You could also install Gen IV 5.3 rods and pistons, which will yield about 10.5:1 due to the flattop piston. I wouldn't recommend milling and a factory piston swap since you'll lose piston to valve clearances, which may require flycutting the pistons or getting aftermarket pieces with valve reliefs.
As for the duration, there are more cam numbers than what is presented at the typical .050" lift mark. However, the numbers do give you a decent idea on how the cam is going to act in the motor. Typically, the longer the duration in which the valve is open, the more the engine is going to want to breathe. Now, it isn't as simple as "more air = good," since there are limitations in place. A few being cylinder size, engine size, and valve size. So, if the camshaft is allowing more air to come in, the engine may need more RPM to effectively take advantage of that air since it can only displace so much due to its inherent limitations. Hence the powerband moving up in the RPM range. This is why a 245/257 cam in a 7.0 could act like a 225/237 cam in a 6.0 within the same RPM range. If you reversed the situation and put the 225/237 in the 7.0, it would make power much earlier on, but it may run out of breath as the RPMs climb. The 245/257 in the 6.0 would most definitely sound gnarly, but your low-end torque would be gone and it would need to rev much higher to produce power. This is a rudimentary example, but hopefully it helps.
The first thing you need to decide is if you are going to bump compression, and if so, how. Once you get that squared away, the other pieces of the engine puzzle will fall into place.
On a side note, depending upon your budget and creativity, you aren't just limited to a T56, NV3500, or a Chevy transmission at all. You could use the Aisin AR5, Nissan CD009, Getrag 265, or a bunch of other 5 or 6 speed transmissions. Each choice comes with its own challenges and cost.
http://garage.grumpysperformance.com...pec-card.1477/
The larger LS1 valves will allow for more airflow, but they won't increase compression. To increase compression on your motor, you can mill the heads up to .030" and use a Cometic .040" gasket. You could also install Gen IV 5.3 rods and pistons, which will yield about 10.5:1 due to the flattop piston. I wouldn't recommend milling and a factory piston swap since you'll lose piston to valve clearances, which may require flycutting the pistons or getting aftermarket pieces with valve reliefs.
As for the duration, there are more cam numbers than what is presented at the typical .050" lift mark. However, the numbers do give you a decent idea on how the cam is going to act in the motor. Typically, the longer the duration in which the valve is open, the more the engine is going to want to breathe. Now, it isn't as simple as "more air = good," since there are limitations in place. A few being cylinder size, engine size, and valve size. So, if the camshaft is allowing more air to come in, the engine may need more RPM to effectively take advantage of that air since it can only displace so much due to its inherent limitations. Hence the powerband moving up in the RPM range. This is why a 245/257 cam in a 7.0 could act like a 225/237 cam in a 6.0 within the same RPM range. If you reversed the situation and put the 225/237 in the 7.0, it would make power much earlier on, but it may run out of breath as the RPMs climb. The 245/257 in the 6.0 would most definitely sound gnarly, but your low-end torque would be gone and it would need to rev much higher to produce power. This is a rudimentary example, but hopefully it helps.
The first thing you need to decide is if you are going to bump compression, and if so, how. Once you get that squared away, the other pieces of the engine puzzle will fall into place.
On a side note, depending upon your budget and creativity, you aren't just limited to a T56, NV3500, or a Chevy transmission at all. You could use the Aisin AR5, Nissan CD009, Getrag 265, or a bunch of other 5 or 6 speed transmissions. Each choice comes with its own challenges and cost.
03-26-2018, 01:25 PM
#13
Okay so I'm doing my first swap (5.3 into an 06 Colorado Xtreme) and my goal is to make a bit over 400hp at the rear wheels N/A.
- 2000 5.3 LM7 (currently with 862 casting heads)
- Crane Cams 224/232 Cam w/ springs (https://www.summitracing.com/int/par...9121/overview/)
- Speed Engineering Long Tube Headers (https://www.speed-engineering.com/sp...1999-2006.html)
My question is for the cam I want to use I need 11:1 compression ratio and stock the LM7 makes 9.5:1. What is the best and safest avenue for me to increase the compression to what is required ? I spoke to a friend about swapping the heads and he said 706 casting heads should get me close but everything I read says the 862's and 706 are identical.
I'm sure this is a common question, could anyone offer me some help and possibly an avenue that I could teach myself how this all works ?
Thanks!
- 2000 5.3 LM7 (currently with 862 casting heads)
- Crane Cams 224/232 Cam w/ springs (https://www.summitracing.com/int/par...9121/overview/)
- Speed Engineering Long Tube Headers (https://www.speed-engineering.com/sp...1999-2006.html)
My question is for the cam I want to use I need 11:1 compression ratio and stock the LM7 makes 9.5:1. What is the best and safest avenue for me to increase the compression to what is required ? I spoke to a friend about swapping the heads and he said 706 casting heads should get me close but everything I read says the 862's and 706 are identical.
I'm sure this is a common question, could anyone offer me some help and possibly an avenue that I could teach myself how this all works ?
Thanks!
https://www.google.ca/amp/www.hotrod.com/articles/ls-cam-test-comparison/amp/
That's the link to the cam tests they did. Like I said I'm completely new to all of this and trying to do my research to learn. In the article they make it sound like it's basically a drop in cam with spring upgrades required but then going to summits page they say it requires an 11:1.
How much would have to be milled to make an 11:1 CR? Is that even safe to do or would I be running into piston clearance issues?
Is there a better way to make my goals with a different cam setup
That's the link to the cam tests they did. Like I said I'm completely new to all of this and trying to do my research to learn. In the article they make it sound like it's basically a drop in cam with spring upgrades required but then going to summits page they say it requires an 11:1.
How much would have to be milled to make an 11:1 CR? Is that even safe to do or would I be running into piston clearance issues?
Is there a better way to make my goals with a different cam setup
Thanks a tonne for all the explanations man.
You are right in the assumption that the goal for the truck is to just have a fun summer driver that I can get on from time to time and take to a track day for ***** here and there. I think I would prefer the truck to be torque-y (assuming I can put that power down on a 275 rear tire possibly with traction bars).
The truck will be a manual trans which is another hurdle I've been trying to overcome as I'd like to get a t56 into it but with the finances how they are it will more than likely be an nv3500 from an s10 this year and be upgraded next year. (gearing in an nv3500 is not optimal and I'd like to build the truck with the idea in mind that it will be getting a t56 or tko for the following summer).
Sorry for sounding stupid here, you are saying to have the 862's machined for larger intake valves. This is just to allow more air into the chamber faster ? Would this increase compression? If I did this in addition to decking the heads back a bit would that be ideal ?
In regards to the cam I look at the numbers and try to get a hold as to what they all mean. What the a larger vs smaller difference in the intake and exhaust duration change (ie. 218/224 vs 224/232)? I'd like to have a cam that is a little "lope-y" and as the vehicle is going to likely be staying naturally aspirated I'd like to get as much gain from the cam and changes to the heads as possible while obviously keeping the truck strong throughout the rev range. (if anything id like to have low end torque and strong power through the mid range ... what does this look like in the way of the cam?)
You are right in the assumption that the goal for the truck is to just have a fun summer driver that I can get on from time to time and take to a track day for ***** here and there. I think I would prefer the truck to be torque-y (assuming I can put that power down on a 275 rear tire possibly with traction bars).
The truck will be a manual trans which is another hurdle I've been trying to overcome as I'd like to get a t56 into it but with the finances how they are it will more than likely be an nv3500 from an s10 this year and be upgraded next year. (gearing in an nv3500 is not optimal and I'd like to build the truck with the idea in mind that it will be getting a t56 or tko for the following summer).
Sorry for sounding stupid here, you are saying to have the 862's machined for larger intake valves. This is just to allow more air into the chamber faster ? Would this increase compression? If I did this in addition to decking the heads back a bit would that be ideal ?
In regards to the cam I look at the numbers and try to get a hold as to what they all mean. What the a larger vs smaller difference in the intake and exhaust duration change (ie. 218/224 vs 224/232)? I'd like to have a cam that is a little "lope-y" and as the vehicle is going to likely be staying naturally aspirated I'd like to get as much gain from the cam and changes to the heads as possible while obviously keeping the truck strong throughout the rev range. (if anything id like to have low end torque and strong power through the mid range ... what does this look like in the way of the cam?)
Have your 5.3 heads CNC ported if you can afford it. Companies like Frankenstein Engineering Dynamics, Venom Racing Engines, Late Model Engines and more have great CNC programs for the factory heads. That should get you about 35-40 more HP. Have the heads milled about .025" to increase compression.
Next, use our Titan 4 LS1 camshaft: http://www.cammotion.com/camshafts/t...227-232-113-4/
This camshaft will have the wide powerband you need to help on shift recovery with your wide ratio manual transmission. And, will have sufficient piston-to-valve clearance if you do not mill your heads more than about .025"
Get yourself some 1 3/4 long tube headers, cold air intake and find the best tuner in your area.
I think this combination will give you the best powerband for your build, have a great idle sound and very good drivability.
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The Switch Is On To Cam Motion!
40 years of Championship Winning Experience • Superior 8620 Steel Camshaft Cores • Quiet, Smooth & Powerful Lobe Design • Virtually Unlimited Lift and Duration Combinations • Finish Polished For Quiet Operation • Cam Doctor Printout With All Cams
The Industry's Best Customer Service
www.CamMotion.com • ☎ 225-926-6110 • Like Us On Facebook!
03-26-2018, 07:01 PM
#14
When I said "the big names", I was referring to Comp, Crane, Lunati, Isky, etc.; the traditional ones. They just don't seem to have embraced these motors and really plugged themselves in. Seems like they offer the same grinds they always have, just on a different blank. Those others really do. I'd add BTR to my short list too BTW.
For CNC head porting, both Katech and Livernois have CNC programs they'll run for $500. No idea which is "better" in any particular way. Regardless, just about any has GOT TO BE better than as-cast. You just wanna find one that is skewed towards what you want in your particular situation: broad torque range, high-RPM flow/power, or whatever.
For CNC head porting, both Katech and Livernois have CNC programs they'll run for $500. No idea which is "better" in any particular way. Regardless, just about any has GOT TO BE better than as-cast. You just wanna find one that is skewed towards what you want in your particular situation: broad torque range, high-RPM flow/power, or whatever.
03-27-2018, 04:13 PM
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On a side note, depending upon your budget and creativity, you aren't just limited to a T56, NV3500, or a Chevy transmission at all. You could use the Aisin AR5, Nissan CD009, Getrag 265, or a bunch of other 5 or 6 speed transmissions. Each choice comes with its own challenges and cost.
03-27-2018, 04:14 PM
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For your combo this is what I would suggest:
Have your 5.3 heads CNC ported if you can afford it. Companies like Frankenstein Engineering Dynamics, Venom Racing Engines, Late Model Engines and more have great CNC programs for the factory heads. That should get you about 35-40 more HP. Have the heads milled about .025" to increase compression.
Next, use our Titan 4 LS1 camshaft: http://www.cammotion.com/camshafts/t...227-232-113-4/
This camshaft will have the wide powerband you need to help on shift recovery with your wide ratio manual transmission. And, will have sufficient piston-to-valve clearance if you do not mill your heads more than about .025"
Get yourself some 1 3/4 long tube headers, cold air intake and find the best tuner in your area.
I think this combination will give you the best powerband for your build, have a great idle sound and very good drivability.
Have your 5.3 heads CNC ported if you can afford it. Companies like Frankenstein Engineering Dynamics, Venom Racing Engines, Late Model Engines and more have great CNC programs for the factory heads. That should get you about 35-40 more HP. Have the heads milled about .025" to increase compression.
Next, use our Titan 4 LS1 camshaft: http://www.cammotion.com/camshafts/t...227-232-113-4/
This camshaft will have the wide powerband you need to help on shift recovery with your wide ratio manual transmission. And, will have sufficient piston-to-valve clearance if you do not mill your heads more than about .025"
Get yourself some 1 3/4 long tube headers, cold air intake and find the best tuner in your area.
I think this combination will give you the best powerband for your build, have a great idle sound and very good drivability.
Is that not way too large of a cam as was mentioned above ? With such large lift and duration would I not lose out on low end power ? In addition I was told that 600 lift is about the max that you can go with a 5.3 before having to worry about Piston to valve clearance (and even less if im milling the heads ?).
03-27-2018, 06:22 PM
#17
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In many cam discussions on this forum, it is often mentioned that PTV is duration- and overlap-related, not lift-related. When the valves are fully open, the piston is well down the cylinder. Where things get dicey is in high overlap situations, where both valves are open to a degree simultaneously.
But to recap, long-duration, high-overlap cams are the concern with PTV
But to recap, long-duration, high-overlap cams are the concern with PTV
03-27-2018, 06:54 PM
#18
PTV is duration- and overlap-related, not lift-related
The valves are at max lift when the piston is halfway down the bore, more or less; 2" or so away from the valves. Max lift in the .001"s is NOT the issue.
HOWEVER:
When the piston is at TDC, not the firing instance but the other one where the exh is closing and the int is opening, THAT'S where the problem can crop up. At that point, the piston is ACTUALLY up somewhere that the valves can be in its way. Cams that hold the exh open REAL late, or open the int REAL early, will cause clearance issues. That can be EITHER the result of just overall long-duration lobes, OR, advancing or retarding the cam to where either the exh is late or the int is early. Not usually an issue in any kind of remotely streetable build unless there's an assembly mistake.