Valve Lash on a '71 455 HO
 

I've got a '71 T/A with the 455 HO engine. I'm running a Comp Cams Xtreme energy cam with matching lifters, springs, retainers, locks & pushrods.

I'm using the big block chevy style rocker studs to make the valvetrain adjustable.

Looking for opinions on what to set the valve lash at. Zero plus 1/4 turn, 1/2 turn, 3/4 or other? What do you guys usually do on an adjustable valvetrain?

I don't remember... 1/2 or 1 turn.

If the plunger in the lifter has the std 1/8" travel i would use 1 full turn from zero.
That would place the plunger about halfway into the lifter.

What did the instructions for the lifters say to adjust them at? Different lifters can have different adjustment amounts... best to read & follow what comp says to adjust them to or call comps tech line.

valve lash
 

Make sure to Soak the lifters overnight in oil.
Follow the firing order.
Turn the push rod with fingertips until you feel the drag change.
1/2 turn and that should be good.
Loser the better without clatter.

I could not of said it better.

Thanks for the input. I did reach out to Comp Cams also, but am waiting on a reply. Figured the Pontiac specialists here would know what's up.

Better to call their tech line, emails can take a lot longer. Or if you have it, look at the instructions that came with the lifters.

Im sure 1/2 past zero lash is a good ballpark or might be the correct setting... but different lifters can & do have different adjustment specs, even the same brand can have different adjustment based on the type of lifter.

I always used zero lash plus 1/2 turn.

Same procedure slunkwerks noted in the earlier post.