After reading the recent thread on valvetrain geometry, I was curious if my speed pro 1.6 ratio stamped steel rockers will hold up to the LT4 springs and LT1 cam. This is a TBI 350 I am puttting together for my 95 truck.

Lonnie

 

If you have part# 12551483 springs,which the GM Performance parts catalog states for, LT4/ZZ4 engines,then they should be ok because your lift won't be over .500".................................
BUT
It also states that the outside dia. 1.32" which means you'll probably have to have your spring seats machined.
I'm not familiar with the heads you have,but I would measure the seats to see what springs will fit without machining.

That is of course unless you don't mind having your seats machined.

 

Yes, GM part# 12551483 with 10212808 retainers. I had them setup on a pair of 083 castings. Maximum lift should be around .480 with the 1.6 rockers. I was concerned about the spring pressure and if the rockers i have are strong enough.

Thanks
Lonnie

 

I've got Comp Cam 1.6 roller tips with an LT1 cam,And I went with ZZ3 springs which are 1.273" and they work fine....

 

If you purchase the LT4 "hot cam" springs in a complete set from GMPP (P/N 12495494) they are less expensive. The LT4 ovate wite springs don't have extreme seat pressure like some springs, so the stamped rockers should work fine up to about 5,500 RPM with valves that don't exceed 105g. If you install heavier valves and/or push rods, your results may vary.

IIRC, the seat pressure at 1.710" was around 110#, versus the 85# rating of the stock springs. And those springs are actually rated for safe operation to lifts of at least 0.525" (LT4 "hot cam" specs).

 

Yes I did order kit #12495494 and the total was less than $40.
Thanks for everyones reply, I guess I am being over cautious.

Lonnie