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Howdy y'all! I'm pretty new to the LS world for building engines since my other trucks have been Fords. I have a 2003 Silverado extended cab short bed 2wd with 230k on the clock. The previous owner lifted it six inches (I know, why lift a 2wd) and it has 35s. He claimed the 4l60e had been "built" but I don't know how true or to what extent. It is my daily driver and I tow my 20ft ski boat and 20ft flatbed occasionally. After taking said boat to the lake a couple times last year after I got this truck I'm not very happy with the lack of power. It might be because my previous truck was a Ford excursion with the v10, who knows. I am building a new 5.3 lm7 to swap out with the current one. I'm not looking to have a speed demon or anything, just something that is overall better than stock. Here's my idea so far...
Gen 3 5.3 iron block (cleaned and honed with new cam bearings)
Two sets of 706/862 heads (one to go on in stock form and one for me to get started on learning to do head work).
Gen 4 5.3 pistons and rods (should bump compression ratio to 10.5ish)
Gen 3 crank (yes the rotating assembly will be balanced due to heavier rods and pistons)
4l60e with stock converter
I need some help with cam choice. I've been searching through the all knowing Google and have seen so many different answers, on this forum and others, that my mind is going numb. I would like to get as much as I can but still maintain streetability. At this point putting a converter in it isn't in the budget and I'd like to run on pump gas. I saw this cam motion cam in a thread and after reading through it, it seems like it's what I'm looking for. I don't have a problem changing springs so would the high lift version be better vs low lift?
Not that I can give a great recommendation, because I usually look for advice in this area myself, but I ran a TSP Torquer V2 in a 5.3 Yukon about 10 years ago and loved it.
First off before I comment I'll say I have been driving 5.3 trucks for the last 10 years. And I'm in a similar situation as you are.
After years of pondering this the absolute best thing you can do is not do a 5.3 build. You need cubic inches. Badly. Especially with having a 4L60 a lift, and big tires. There's only so much a 5.3 can do.
Either bore the 5.3 out while it is apart or grab a 6.0 bottom end and put the 706 heads on and go from there. The 6.0 would be a far better choice. Or boring a 6.0 some would be best. But a 6.0 bottom end will still work wonders over the 5.3
As said always do the highlift truck cam option. When there are two of the same cams in different lifts, if you look at the dyno overlays the high lift gains power everywhere over the low lift.
If you keep a stock stall, you'll need a mild cam, and a mild cam in a 5.3 isn't going to be much different than it is now. You'll gain 40 ish hp and 20 ft lbs or tq, and it won't be down low where you are towing.
If you tossed in a bone stock 6.0 you'd be far happier than building the 5.3 and putting in a small cam. That one point of compression will give you approx 4% more power. That's about 15 hp or so. The cam 20-40 hp, but not much torque. You need torque and you need it down low. Camming the 5.3 is gonna kill some of your low end. You're gonna hate towing with a cammed 5.3 with a stock stall.
If anything I would do a stock 6.0 and a small stall way before I did a mildly built 5.3 with a mild cam and stock stall.
Have you ever had a higher rpm stall before? They transform the vehicle and make it feel like you added 200 ft lbs down low, cause you kinda do through torque multiplication.
Last edited by 00pooterSS; 03-04-2020 at 04:53 PM.
First off before I comment I'll say I have been driving 5.3 trucks for the last 10 years. And I'm in a similar situation as you are.
After years of pondering this the absolute best thing you can do is not do a 5.3 build. You need cubic inches. Badly. Especially with having a 4L60 a lift, and big tires. There's only so much a 5.3 can do.
Either bore the 5.3 out while it is apart or grab a 6.0 bottom end and put the 706 heads on and go from there. The 6.0 would be a far better choice. Or boring a 6.0 some would be best. But a 6.0 bottom end will still work wonders over the 5.3
As said always do the highlift truck cam option. When there are two of the same cams in different lifts, if you look at the dyno overlays the high lift gains power everywhere over the low lift.
If you keep a stock stall, you'll need a mild cam, and a mild cam in a 5.3 isn't going to be much different than it is now. You'll gain 40 ish hp and 20 ft lbs or tq, and it won't be down low where you are towing.
If you tossed in a bone stock 6.0 you'd be far happier than building the 5.3 and putting in a small cam. That one point of compression will give you approx 4% more power. That's about 15 hp or so. The cam 20-40 hp, but not much torque. You need torque and you need it down low. Camming the 5.3 is gonna kill some of your low end. You're gonna hate towing with a cammed 5.3 with a stock stall.
If anything I would do a stock 6.0 and a small stall way before I did a mildly built 5.3 with a mild cam and stock stall.
Have you ever had a higher rpm stall before? They transform the vehicle and make it feel like you added 200 ft lbs down low, cause you kinda do through torque multiplication.
I totally agree that more displacement would be ideal. Unfortunately, everyone around my area seems to think the 6.0s are made of gold. For me to get into a 6.0 I'd already be 3/4 of the way (budget wise) into the 5.3 build.
I have not driven or been in a truck with a higher stall converter. I'm a Chevy tech and assembly is easy for me, it's the picking of the right parts to assemble that is tricky.
I’m honestly not confident that you’ll be happy in the end with your intended plan. As mentioned above, I would strongly urge you to consider a 6.0 swap. The displacement is going to give you what you need/want. I’ve been exposed to these 5.3s since they came out in ‘99, to me they are total slugs in these trucks. A LQ4/LQ9 makes a world of difference especially in the area of the powerband that is most important for what you do with the truck. To me, that’s the key of this all. If you have the chance, look at some stock engine dynos and compare the results at every rpm between both motors, it’s rather substantial. I would sell the 5.3 and pick up a stock 6.0 and call it a day. It may be enough as-is, if not you’ve at least got a better platform to work with. Gears may be a good idea too. Just my .02.
Agree that more cubes would be the way to go, but then he not only needs the 6.0, but the 4L80E to go with it.
If sticking with the 5.3L go with the high lift version of the cam you listed, some home porting, and long tube headers.
He wouldn't need a 4L80E. There were several vehicles that came from the factory with 6.0 LQ4 and LQ9 motors and had either the 4L60E or 4L65E transmission (i.e. Silverado SS, Denalis/Escalades, Hummer H2, etc.). Automatic 6.0 LS2 vehicles got 4L65Es or 4L70Es depending on vehicle, etc. 4L80Es were in the 6.0 1500HD and 2500 series trucks. 4L80E is definitely more stout but the good news is that both can be used.
Last edited by StealthFormula; 03-05-2020 at 12:36 PM.
I totally agree that more displacement would be ideal. Unfortunately, everyone around my area seems to think the 6.0s are made of gold. For me to get into a 6.0 I'd already be 3/4 of the way (budget wise) into the 5.3 build.
I have not driven or been in a truck with a higher stall converter. I'm a Chevy tech and assembly is easy for me, it's the picking of the right parts to assemble that is tricky.
I can get them from around 1000-4000 around here. Depends where I look. Junk yards and ebay want a million dollars for them. Found several people in face book groups selling them cheap. As said above you can sell the 5.3 for a good portion of the cost of the 6.0. That's my plan with my current truck. Sell my 5.3 and put the money toward a 6.2
If you want more from the 5.3. Do intake, headers, tune, and gears. Maybe a stall. That will do a lot more for you than a small cam will. And it's all transferable to a 6.0 when you get one.
A 93 tune goes a long way too. That's what I did with my 04 5.3. Made a big difference. Your setup isn't the best candidate for a cam swap. Big heavy truck thats lifted with big tires and tows, mixed with a small motor and a cam is likely to leave you pretty unhappy.
I can get them from around 1000-4000 around here. Depends where I look. Junk yards and ebay want a million dollars for them. Found several people in face book groups selling them cheap. As said above you can sell the 5.3 for a good portion of the cost of the 6.0. That's my plan with my current truck. Sell my 5.3 and put the money toward a 6.2
If you want more from the 5.3. Do intake, headers, tune, and gears. Maybe a stall. That will do a lot more for you than a small cam will. And it's all transferable to a 6.0 when you get one.
A 93 tune goes a long way too. That's what I did with my 04 5.3. Made a big difference. Your setup isn't the best candidate for a cam swap. Big heavy truck thats lifted with big tires and tows, mixed with a small motor and a cam is likely to leave you pretty unhappy.
I think you would be very pleased and I couldn't recommend it enough if it makes sense financially. At one point my Dad and I both had the same trucks, difference being his had the best of that gen 5.3 and mine the 6.2. The difference was beyond night and day. 6.2 is a hot rod motor for a pickup, especially the 6.2s that come in your generation truck.
x2 on FB marketplace, I've been having good luck on there lately OP.
I think you would be very pleased and I couldn't recommend it enough if it makes sense financially. At one point my Dad and I both had the same trucks, difference being his had the best of that gen 5.3 and mine the 6.2. The difference was beyond night and day. 6.2 is a hot rod motor for a pickup, especially the 6.2s that come in your generation truck.
x2 on FB marketplace, I've been having good luck on there lately OP.
The amount of difference is ridiculous. How they feel, run and pull away from a 5.3 is crazy, I say that because if you look at power numbers alone it doesn't explain the difference/tell the whole story.
And for me I've ran the numbers and it will cost me about 500-800 to do a 6.2 swap. I've found 6.2's with trans and harness for mid 2k range. I can sell the trans and harness and computer for probably 500-800. Sell my 5.3 for 1000 or so, maybe more.
This video sealed it for me. And I use it to demonstrate. These two truck have the same transmission. So no gain from one having an 8 and the other a 6.
One is reg cab short bed 2wd the other a crew cab 4wd. Reg cab is WAY lighter and more modded and gets destroyed. Reg cab has intake headers and tune. Crew cab is a intake and tune only and launched in 2wd, so it wasn't traction that made the difference either. I raced a buddy in a bone stock Yukon denali 6.2 with my truck and this same thing happened. He just ran off and left me. You'll feel this additional power at all times, especially towing and low rpm. These trucks are just too heavy, and add in towing and big tires, to be happy with a 5.3.
It shows cam tests on a 5.3 versus a 6.0. The 6.0 is a square port 6.0, but cathedrals usually make more down low where you're going to want it anyway, plus you'll likely end up with more compression using cathedrals and that will help even more..
The interesting part is a 5.3 with a stage 3 cam makes the same horsepower as a stock 6.0. With headers on the 6.0 it made an additional 10 hp and 13 foot pounds over that. So a cam kit for your 5.3 that will drive like crap will cost 500-1000 depending on which supporting parts you buy. If you sell your 5.3 you can put that 1k toward the 6.0 and whatever you sell the 5.3 for. You'll likely have money left over. Then do headers. You'll have more power than a stage 3 cammed 5.3 and a whole lot more torque.
Plus consider the money not only you'll spend on the cam kit, but the rebuild of the 5.3. If you don't spend that on the 6.0 you're WAY ahead, or spend the same money tor rebuild the 6.0 and still be a little ahead if you run a stock cam. Put a little cam in the 6.0 and you're really making a lot more.
I do honestly appreciate and understand what y'all are saying about going bigger on displacement, however it's just not an option for me. If in the end I'm not happy enough with the 5.3 build then I'll address that in the future. Right now I'm just looking to get a little more out of a 5.3.
I do honestly appreciate and understand what y'all are saying about going bigger on displacement, however it's just not an option for me. If in the end I'm not happy enough with the 5.3 build then I'll address that in the future. Right now I'm just looking to get a little more out of a 5.3.
Sorry but I call bs. If you have the money and ability to pull and rebuild a 5.3 and cam it. You can stick a 6.0 in it.
If you just don't want to. That's cool it's your build.
If you want more out of your particular setup I would not put the primary focus on the cam. You have other areas that would be far better to address. Like gearing. Intake exhaust. High octane tune. Several things.
If you want a cam recommendation for your 5.3, run the Texas Speed Stage 1 cam. High lift is the better choice.
Or the cam you posted about originally. High lift will provide more power, so it's worth choosing that option. Even if you do low lift you should upgrade the valve springs. If you do low lift you can do LS6 springs which are a big upgrade over stock truck springs and only cost $70 for a full set.
Last edited by 00pooterSS; 03-05-2020 at 07:12 PM.
I think y'all have misconstrued what I'm doing somewhat and it is partially my fault. I'm not pulling the current engine out and building it then putting it back in. I picked up a core in good shape (intake to oil pan) from my local yard for $200, I couldn't find a 6.0 for any less than $1000 at the time. I stripped it down to bare block then had it vatted and new cam bearings installed. I'll be assembling this engine on the stand and then swapping out complete units when it is done. I know getting the crank balanced for the gen 4 rods/pistons is throwing my budget a little out of wack, but I'm committed at this point and even if I'm not as happy as I'd be with more displacement, I'll be better off than stock.
I also forgot to mention in my original post that I have a TBSS intake that will go on it, still have to get the throttle body though.
I think y'all have misconstrued what I'm doing somewhat and it is partially my fault. I'm not pulling the current engine out and building it then putting it back in. I picked up a core in good shape (intake to oil pan) from my local yard for $200, I couldn't find a 6.0 for any less than $1000 at the time. I stripped it down to bare block then had it vatted and new cam bearings installed. I'll be assembling this engine on the stand and then swapping out complete units when it is done. I know getting the crank balanced for the gen 4 rods/pistons is throwing my budget a little out of wack, but I'm committed at this point and even if I'm not as happy as I'd be with more displacement, I'll be better off than stock.
I also forgot to mention in my original post that I have a TBSS intake that will go on it, still have to get the throttle body though.
You still have the option of boring that block, or selling it all off, or building it and making a good amount of money on it, profit, and using that to do it right the first time. Just saying.
You have a running driving truck right now it sounds like, so it doesn't seem like you have a time limit. We are just trying to save you from really regretting your choice.
Sorry man, but I think you're gonna be really bummed after all the work and money and it isn't much different than what you have now, or potentially worse (doing a cam in your current setup can easily make your issues you have with it, worse). The cam you chose isn't likely to, but it also isn't going to change much either. That intake, will help top end though. Which again won't do much at all for your current situation.
03-03-2020, 09:54 PM
5.3L build for truck 
