Pat McPherson

I have a 1997 415HP/502MagMPI with approximately 120hours on a rebuild from 2 seasons ago.

I did a basically stock rebuild using the original cam, new GM roller lifters, new GM pushrods, new GM stamped steel 1.7 rockers, and new 502HO valve springs. I bought the new valve-train parts through a GM performance parts dealer. My heads were milled 0.010 the block was not decked.

Last year I bought a set of 1.8 ratio roller rockers and conversion studs with the thought that the added lift would give the engine a little more power. But, I never did get around to installing the new roller rockers.

My question is should I install them this year?

I basically have two concerns:
- Will the valve springs handle the extra lift being that they have been running at 0.482 for 120+hours?
- Will the 1.8 ratio rocker cause any valve-train geometry problems?

One other consideration is the MPI calibration. I believe I can solve any potential lean condition with a little more fuel pressure. I am also running Stainless Marine exhaust.

Has anyone ever install 1.8 rockers on a 454 or 502 Mag? It would seem like an easy way to gain a little punch...

BadDog

For anyone considering;
http://www.scorpionperformance.com/p...onrockers.html

Try calling Scorpion, they may be able to advise.

CStraub can set you up;
[email protected]

Pismo10

I dont think you will, see any performance difference. Heard of a few people who tried it, no miracles. Just going to roller rocker should give you a few hp.

Pat McPherson

Yea, I'm not expecting huge gains.
Desk-top-dyno shows +10 to 15HP with the extra 0.030" of lift. The fact they are roller vs. stamped, maybe another 5 to 10HP.
An extra 20HP is worth the effort of putting them in if I'm not going to create any mechanical issues.
Thanks,