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Highest lift cam for a stock motor lt1??????

Old 10-29-2018, 04:55 AM
  #21  
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Originally Posted by Phoenix'97 View Post
Ah, better! Okay, the heads won't flow past .4 but what RPM will this level be reached at with the cam I am looking at? Since this is a problem I felt I would likely run into, would 200cc capable heads help remedy this problem and accommodate .6 at whichever RPM level this will happen?



The reason I am attracted to the "restrictive" long runner TPI intake is for its additional torque production from 2500 to 4500 RPM, well beyond what my short runner stock intake can produce. On top of not being happy with my off idle torque, wanting a little more at 1500 RPM than what I currently receive with the stock cam, I am not happy with how flat my torque is on up to 5000 RPM. I don't wish to high rev my car to tap into those higher torque numbers when I can achieve them at mid-range RPM and using the fluid dynamics of the TPI intake. These are the aspects of my LT1 engine and factory set-up that I wish to have changed. If it requires some "race car land" know-how to make it happen then fine but the suggestions I have been given ever since I started asking about cam modifications to my car have not been true to what I am looking for, stock daily driver dedicated performance.



For the sake of ease and the sake of performing this build on a budget, the cast iron B-body LT1 heads which flow 200cc would be something for me to consider as opposed to spending $1000+ per head on the same aluminum aftermarket heads. Again, this is what I need to figure out before hand and whether or not this camshaft idea is doable.

You're just speaking word salad here. You need to go get an "engines 101" book and start there.
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Old 10-29-2018, 05:36 AM
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Originally Posted by sbs View Post
You're just speaking word salad here. You need to go get an "engines 101" book and start there.
I can see no one has a real answer to this question posed by both the original poster and myself. How high can you go in cam lift before either your heads or intake are unable to flow what the cam can bring in? I like how the car drives and I like the stock cam, I am sure the original poster felt the same way. However, more lift and more power production from the stock camshaft would make a stock LT1 more enjoyable after 10-years of year-round daily driving with her. This is why we ask such questions, even college students pose such questions to the professors not to be annoying, not to be "trolls" but to satisfy a curiosity or possibly having another perspective that has gone missed that even a professor can appreciate! Here we are posing these ridiculous questions.

I suppose I am going to get all the help I can here...
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Old 10-29-2018, 09:00 AM
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Originally Posted by Phoenix'97 View Post
I can see no one has a real answer to this question posed by both the original poster and myself. How high can you go in cam lift before either your heads or intake are unable to flow what the cam can bring in? I like how the car drives and I like the stock cam, I am sure the original poster felt the same way. However, more lift and more power production from the stock camshaft would make a stock LT1 more enjoyable after 10-years of year-round daily driving with her. .
You are entering into the world that require specifics, and not just generalized questions.

Super high cam lift numbers means aggressive ramp rates, which means expensive/quality springs and retainers are required. But, you may be limited by the stock spring pad on a OEM head. All you may succeed in doing is beating up a lot of valve train parts for the sake of "proving the internet wrong"

Quick google on stock LT1 head flow. See how its just dead past .4 on the intake side? So yes, you may gain something by tossing the valve open faster via a tall lift, but, thats one aspect to a large puzzle that you are not looking at.

"LIFT: INTAKE: EXHAUST:
.100 59 44
.200 121 98
.300 169 127
.400 200 149
.500 203 160
.550 202 160
.600 ---- ----"

While performance wise, GM engineers are looked down at, for making the most out of a engine for the 90% of people who drive them, GM does great. I think you would be hard pressed to improve upon their work within the small window you are focused on.

Have you talked to a custom cam designer?
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Old 10-29-2018, 01:11 PM
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This guy is a tool.
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Old 10-29-2018, 01:37 PM
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.525 lift seems to be the sweet spot for performance on an untouched stock lt1 head.
One of the reasons GM used .525 lift on the hotcam.
My Lloyd speced cam uses .533 lift on my stock heads with valve job.
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Old 10-29-2018, 08:31 PM
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Originally Posted by Shownomercy View Post
You are entering into the world that require specifics, and not just generalized questions.

Super high cam lift numbers means aggressive ramp rates, which means expensive/quality springs and retainers are required. But, you may be limited by the stock spring pad on a OEM head. All you may succeed in doing is beating up a lot of valve train parts for the sake of "proving the internet wrong"

Quick google on stock LT1 head flow. See how its just dead past .4 on the intake side? So yes, you may gain something by tossing the valve open faster via a tall lift, but, thats one aspect to a large puzzle that you are not looking at.
Okay, so pretty much the best I can do with my stock cam is give it higher ratio rockers. I believe 1.7 is the highest you can go for measured increases in performance or in my case, lower and mid-range torque.


Originally Posted by Shownomercy View Post
While performance wise, GM engineers are looked down at, for making the most out of a engine for the 90% of people who drive them, GM does great. I think you would be hard pressed to improve upon their work within the small window you are focused on.
Well, you guys manage to pull off 12 second race cars out of what these GM engineers supplied the corporation with for street driving. Wouldn't someone argue you managed to improve upon what they were able to engineer given the government mandates and restraints?


Originally Posted by Shownomercy View Post
Have you talked to a custom cam designer?
Not yet. I want to make sure I know what I am looking for instead of being talked into a cam which may not be what I really wanted. I have my notion of performance while the cam designer is used to guys wanting race cars.


Originally Posted by 350 groundpounder View Post
.525 lift seems to be the sweet spot for performance on an untouched stock lt1 head.
One of the reasons GM used .525 lift on the hotcam.
My Lloyd speced cam uses .533 lift on my stock heads with valve job.
So, pretty much we have an idea of where the limit is at then. I was even thinking about the "Sleeper Cam" on Lloyd's website and the lift figures it has, 212/222 .563/.562 114 LSA. . I wonder what such a cam would yield with a wider lobe and adjusted duration to match my stock cam or what would be the absolute best for an LT1 engine. I assume this cam requires Lloyd ported heads and valvetrain upgrade, eh?

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Old 10-29-2018, 08:37 PM
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No, my point was its easy to make a race car cause you accept that you sacrifice the ability to have it be a car that 90% of the population could drive with out knowing its not factory.

(for the most part)
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Old 10-29-2018, 10:16 PM
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Stock valve springs will limit lift due to coil bind over .500 lift exact number will vary but needs checked. Aftermarket high lift high pressure along with conical springs will allow for higher lift. The max lift should match airflow, no benefit to have too much lift. Not sure about 1.7 rockers on stock displacement unless you have a special "fast action" cam. IMO they are unnecessary unless you're doing a stroker where internal rotating clearance is a concern. 1.7 also allows for a larger base circle or a camshaft.with less flexing.
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Old 10-29-2018, 10:21 PM
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LEs sleeper cam would be great for your low-mid range torque. I was after the same type of powerpand. I like low-mid range power 1200-5000rpm.
LE speced me a 215/224 with a 112 lsa.
My car has torque off idle and the mid range 3000-4500rpm is nasty.
i have a m6 trans, 342 gears.
it ran 100mph in the 1/4 stock.
with this tiny cam and bolt ons it runs 107-110mph 1/4's now and drives like stock.
I went with 1 5/8 headers from mac instead of 1 3/4 headers like most usually do, this prob aids in low end torque. This is my daily driver March-October.
Now my Saturday Night Special ride is a 97 SS M6.
LE ported trick flow heads, 383 stroker, ported stock intake, 58mm TB, 1 3/4 headers, to a 4 inch mufflex exhaust, stage 2 spec clutch and a 410 geared 8.8 ford rear end with custom forged axles. This car pushes the torque curve up to around a 4-4500 rpm peak. Whereas the stock headed baby cam car peaks around 3000-3500.


Last edited by 350 groundpounder; 10-29-2018 at 10:27 PM.
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Old 10-29-2018, 10:49 PM
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Without having reads all that's posted here, I will say this...……..stock LT1 heads hit their peak flow right around the .600" mark. Any lift more than that and you'll have airflow turbulence and power production will suffer.

Have a good evening.

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Old 11-01-2018, 08:56 AM
  #31  
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LS7 is an emission cam too. That's why the duration is so small. You'd be giving up a ton of power by running a cam with only 200 degrees of duration. LS7 engines pick up a **** ton of power when you swap the stock cam for something big.
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Old 11-02-2018, 05:55 AM
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Originally Posted by joelster View Post
LS7 is an emission cam too. That's why the duration is so small. You'd be giving up a ton of power by running a cam with only 200 degrees of duration. LS7 engines pick up a **** ton of power when you swap the stock cam for something big.
With regards to my LT1 and what I am looking for, I am trying to explore options for very mild stock-like cams. I may even be content with an aftermarket reproduction of the LT4 cam (not the hot cam) at 115 lobe separation with better lift than the stock LT1 cam. I would like to keep the separation at 117 and explore what more lift and slightly adjusted duration can do for my set-up that I have in mind for the future build. For me, it's not so much about making a ton of power but trying to improve upon the off-idle/low-rpm torque that I want more of out of a stock cam without using too low of a duration and too low of lift tow camshaft, like that from an L31 or B-body LT1. It won't work very well with the intake I want to use which is why a stock 117 separation cam was stated to work the best with the intake.

Also, I know this is a juggling act, but aside from emissions doesn't a wider lobe separation help to give you better fuel economy? The LS7 is given a good EPA rating for a 7.0L engine and with a 120 lobe separation from a tone-down of power, I can start to see how it is achieved. This is the balance I wish to maintain with my car simply because she is more of a daily driver for me than merely a spring/summer only toy or weekend only car.
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Old 11-02-2018, 11:56 AM
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Originally Posted by Phoenix'97 View Post
I may even be content with an aftermarket reproduction of the LT4 cam (not the hot cam) at 115 lobe separation with better lift than the stock LT1 cam.
The lt4 cam has less lift than the stock cam...
it gets it's increased lift at the rocker.

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Old 11-02-2018, 06:48 PM
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Originally Posted by fbody_brian View Post
The lt4 cam has less lift than the stock cam...
it gets it's increased lift at the rocker.
Well, there goes that suggestion, ha ha! I know about the 1.6 rockers with the LT4 cam but didn't realize it had less lift, which defeats the purpose behind why I would be interested in it. So, they narrowed the separation yet decreased lift but used 1.6 rockers. I think I am starting to see how the process works.

I am still thinking a custom grind will be in order but it really is going to be something close to my stock cam or the 1988-1989 L98 cam yet inspired by the LS7 cam with higher lift. Depending on what they come up with and what simulated torque curves provide, perhaps it would be worthwhile to go the full 120 in separation.
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Old 11-07-2018, 12:26 AM
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Originally Posted by Phoenix'97 View Post
.Also, I know this is a juggling act, but aside from emissions doesn't a wider lobe separation help to give you better fuel economy?.......
Typically, a wider LSA will work to reduce valve overlap which aids in low-RPM engine efficiency. So yes, better gas mileage often results. That being said, a wider LSA will also flatten your torque curve and will not always increase low RPM torque in any appreciable manner.

You want low RPM grunt? I suggest more gear......just like I always have.

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