.600" lift for daily driver?
TECH Regular
Joined: May 2023
Posts: 403
Likes: 134
From: Franconia, PA
The ls9 cam is a terrible choice for almost anything. The only reason it is acceptable for the factory ls9 is because the complete lack of low end torque is made up for by having a big PD blower on the engine. Without instant off-idle boost available, that cam will have the lowest torque of almost any option available.
Thread Starter
TECH Fanatic
Joined: Jul 2022
Posts: 1,017
Likes: 384
From: Alaska
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. I tend to think that using the minimum required lift spring would be best in this scenario, like the pac 1218 spring, which had 130lbs of seat pressure and 310lbs of pressure at .600 lift.
I probably wouldn't use a .600 lift cam unless you were swapping lifters. The stock lifters are often close to if not older than 20 years, and a .550 lift cam would treat them better.
. I tend to think that using the minimum required lift spring would be best in this scenario, like the pac 1218 spring, which had 130lbs of seat pressure and 310lbs of pressure at .600 lift.
I probably wouldn't use a .600 lift cam unless you were swapping lifters. The stock lifters are often close to if not older than 20 years, and a .550 lift cam would treat them better.
. It is a fact that these particular LQ4 lifters are 20 years old. I will be using new lifters on this motor. Concerning the valve spring choice: If I DO talk myself into a .600" lift short duration cam, is it you opinion that the PAC1218 listed MAX lift.600" would be the best choice, and NOT PAC 1219?
... Stock rockers planned, upgrayyd Pushrods to .080" wall. " Think it'll live? "
Just to add a new twist to the discussion. In a first as far as I am aware of, it seems that there may be a bad batch of PAC springs floating around recently. There has been some discussion on yellowbullet about it. They have always been my trusted go-to spring source.
edit-- Both threads I saw on the subject were regarding the same valve spring, with no part numbers listed and allegedly came on heads that were already assembled. I doubt the person reporting the issue could even say for sure they were legit PAC springs. I hate to be the guy spreading unverified rumors.
edit-- Both threads I saw on the subject were regarding the same valve spring, with no part numbers listed and allegedly came on heads that were already assembled. I doubt the person reporting the issue could even say for sure they were legit PAC springs. I hate to be the guy spreading unverified rumors.
Last edited by gametech; Oct 6, 2025 at 07:22 PM. Reason: possible rumor
It sucks if it's only a rumor. Because if it is, it was probably started by either a disgruntled customer or a competitor, or both. I looped you in so you could hear about it as soon as I did, which was less than 1/2 hour ago. I run nothing but PAC, and have no intentions of ever running anything else. There's only one other valvespring I've ever run that compares to my PACs for reliability, and those were s set of 16 Comp 26921 dual springs I ran in 2005. Never an issue with them, either. But I prefer PAC.....
The ls9 cam is a terrible choice for almost anything. The only reason it is acceptable for the factory ls9 is because the complete lack of low end torque is made up for by having a big PD blower on the engine. Without instant off-idle boost available, that cam will have the lowest torque of almost any option available.
