Max cam lift with stock heads and pistons??
08-30-2007, 12:03 PM
#1
Melting Slicks
Thread Starter
Max cam lift with stock heads and pistons??
What is the max valve lift that you can run in a 327 with the stock cast iron high performance heads with 2.02/1.6 valves and flat top pistons. I know this will vary by deck heigth, gasket thickness, etc, but just a rough guestimate for my own curiosity would be great.
Thanks!
Thanks!
08-30-2007, 12:45 PM
#2
Race Director
Member Since: Jan 2000
Location: Corsicana, Tx
Posts: 12,607
Received 1,875 Likes
on
913 Posts
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
The only reason lift becomes an issue is the clearance between top of valve guide, retainer, seal (if aftermarket) etc. This is just something that needs to be measured since various valve jobs and parts come up with different stuff. Generally .500 is plenty safe.
P/V clearance is determined by the duration, rate of opening, cam advance and LSA usually. Wider LSA has more clearance.
You generally are Ok with 2.02/1.60 valves with flat tops, but since flat tops never came with 2.02's....it's not OEM stock and who knows where they put the valve pockets? I used some 2.05 valves once with OEM sump pistons and they needed a lot more clearancing than you might have expected.
Anyway, generally cams in the .500 range are OK....but....disclaimer here....your results may vary!
Best to measure stuff.
JIM
P/V clearance is determined by the duration, rate of opening, cam advance and LSA usually. Wider LSA has more clearance.
You generally are Ok with 2.02/1.60 valves with flat tops, but since flat tops never came with 2.02's....it's not OEM stock and who knows where they put the valve pockets? I used some 2.05 valves once with OEM sump pistons and they needed a lot more clearancing than you might have expected.
Anyway, generally cams in the .500 range are OK....but....disclaimer here....your results may vary!
Best to measure stuff.
JIM
08-30-2007, 03:11 PM
#3
Melting Slicks
Thread Starter
I'm running a cam with .498/.504 lift right now. I actually have dished pistons with large valve reliefs. However, i am considering switching to a roller in the future and was just wondering about how much lift you could achieve before issues with valve to piston clearance occured.
It's been so long that i dont even remember what my original pistons looked like-did the original cast pistons in a 1965 327/350hp have domes??
It's been so long that i dont even remember what my original pistons looked like-did the original cast pistons in a 1965 327/350hp have domes??
08-30-2007, 05:08 PM
#6
Team Owner
Member Since: Oct 2000
Location: Washington Michigan
Posts: 38,899
Received 1,857 Likes
on
1,100 Posts
Here's a larger photo of a 2166 (1/8" dome). 
09-04-2007, 12:30 PM
#7
Melting Slicks
Thread Starter
Ah yes, now i remember.
So, what is the most lift somebody is running with stock high performance heads and flat top pistons??
Anybody know max lift before reaching the minimum clearance of .010??
Thanks!
So, what is the most lift somebody is running with stock high performance heads and flat top pistons??
Anybody know max lift before reaching the minimum clearance of .010??
Thanks!
09-04-2007, 12:37 PM
#8
Race Director
With the 2166 psitons, I did a clay check with my ~.500 lift Crower 00321 cam and had about .25" or greater clearance.
Doug
Doug
09-04-2007, 01:44 PM
#9
Team Owner
Member Since: Oct 2000
Location: Washington Michigan
Posts: 38,899
Received 1,857 Likes
on
1,100 Posts
