Pontiac GTO Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
My buddies 1968 lemans 350 2 barrel with powerglide has a bad cam. Was thinking of going with a Summit sum-k2800 ( Duration @.050 204/214 420/442 lift ) The stock cam was a ( U model ) duration ? Lift 375/410. My questions are would the summit cam cause any spring bind? Will it still idle as smooth as stock?
 

·
Premium Member
Joined
·
4,703 Posts
Can't answer about the springs. It will not idle AS smooth, but should be OK. You should match a cam with CARB/INTAKE MANIFOLD & REAR GEARS for optimum gain......are you gonna do a valve job also?
 

·
Registered
Joined
·
18 Posts
Discussion Starter #3
No not doing a valve job. Compression checks out ok. There is a pretty good jump on the intake lift. We may just go with a standard replacement from a parts place so he has a good idle.
 

·
Super Moderator
Joined
·
5,142 Posts
No not doing a valve job. Compression checks out ok. There is a pretty good jump on the intake lift. We may just go with a standard replacement from a parts place so he has a good idle.
The 254 cam has an advertised I/E duration 269/277 with a LSA of 113, the Summit K2800 has an advertised I/E duration 262/272 with a LSA of 112.
The idle may be a little choppy with a 112 LSA but not noticeable. The K2800 cam or a 066 would be a good replacement for the 254. The springs should be ok,
 

·
Super Moderator
Joined
·
5,744 Posts
My buddies 1968 lemans 350 2 barrel with powerglide has a bad cam.
That's not a powerglide, unless someone has swapped in a chevy transmission. Pontiac 2-speed automatics (Super Turbine 300) are different transmissions than powerglides.

Was thinking of going with a Summit sum-
k2800 ( Duration @.050 204/214 420/442 lift ) The stock cam was a ( U model ) duration ? Lift 375/410. My questions are would the summit cam cause any spring bind? Will it still idle as smooth as stock?
You should be ok, spring bind wise. Biggest concern is static compression ratio and tendency towards detonation. If you're changing the cam anyway, it might be wise to use one with a later intake close event to stay out of trouble. Which heads does it have?

Bear
 
1 - 7 of 7 Posts
Top