[laitch]

I'm confused about maximum valve lift on stock vortec heads. I've heard different numbers from different sources. Some say .420" and another says .450". Where do I find the correct number? Chevy High Performance says there is a total .450" retainer to seal clearance but I don,t understand because GM sells thier 350 H.O. Crate Motor with stock Vortec heads and valve lifts of .435"I and .460"E. How is this possible?

[BOBCRMAN@aol.com]

.450 is about max, gm uses a different retainer on vortec heads thats how they get away with the extra lift. if you use aftermkt or stock chevy retainers watch out.

[JoeDog]

I've been using a Lunati cam with .480 lift with my stock vortec heads for about 3 years now and i haven't had any problems. I drive the car alot and race it too.

[S10prostreet]

You can use your vortex heads with your lift. They make spring and retainer kits that raise your open spring height. These have special retainers/keepers to do this. There are also smaller wire springs to help with getting the spring clearance you need. Its not to hard to cut down the boss tho and you would be free to sail with more lift.