did a search and came up with mixed answers, I just got my 402 running and it is noisey as hell, Ls6 heads, stock lifters, 7.4 pushrods, stock rockers, comp xer287hr-12 cam i now have roughly .044 of preload, I called the sponsor i got my heads and pushrods from and they said they set thiers up with .030 to .050 of preload, other posts i have read say stock lifter preload should be .080 or more. Any ideas

 

.080+

 

if it is .080+ and i have .044 i would need a 7.44 pushrod or a little longer correct?? And this should help make her a little quieter

 

.080+ 7.4 = 7.48 so round that to 7.5 but I doubt thats going to quieten it down. My 408 is noisy as hell with a comp cam, factory rockers, patriot gold springs, and 7.4 PR's. Ive always heard the extreme lobes on the cams make them extremely noisey.

 

I wonder why i am getting so many different opinions everybody here says .080 i called 3 sponsors today and all said something different, one sain .030 to .050 another said .050 to .060 and the last one said .040. These are stock lifters. wILL it hurt anything if i get it dyno tuned the way it is?? It runs fine it is just noisy. I can always get a checker and get some longer pushrods that should in no way affect the tune as long as i dont go way too far and have valve float issues. I think from the figures i have i should shoot for around a 7.450 pushrod and that will give me .050 more preload than i have now (.044) So that makes total preload .094 or if i got a 7.425 pushrod i would have a total preload of .069 what do you guys think??

 

yeah, what's the deal? What is the acceptable lifter preload range. I've head everything from .02-.125 is normal??

 

Every stock motor I have measured comes in at about 0.100". I think GM would know better than the guys you are calling.