George C....

True GM ls7 lifters require .075 of preload

My 427 is pretty quiet for valve train...
Moral link bar lifters
8" pushrods with .035 preload
20w50 vr1 oil
700 lift springs


Ive done alot of builds over the years and havent needed a shorter pushrod then 7.4, in the older vehicles with a ls6 cam ive used 7.425 push rods

Older lifters had different base cup for push rod ball vs the ls7s


Ac delco parts arent same quality as GM quality



You may also want to check rhe springs being they are BTR...there has been reported failures of the springs... Busted spring will be noisey

lxcoupe

iTrader: (9)

I know this to be case for *most* AC Delco branded parts, but not all. Their wheel cylinders are Chinese made as are their fuel pumps... which makes me wonder what AC Delco parts are actually quality and what aren't.

Atomic

iTrader: (42)

Headers also make it more noticeable than stock cast manifolds.

lxcoupe

iTrader: (9)

I've seen that as well, but in this case there's a log on one side and a cast manifold on the other.

GMCtrk

iTrader: (27)

my rods are 7.325

bisqikss

iTrader: (2)

cam motion cam, yes heads milled 799's. no guides replaced, they were tight. love the cam. this is the 4th cam from them I've messed with.

lxcoupe

iTrader: (9)

Guys, just had a chance to do an oil change with VR1 20w50. I started the truck up and I would say it was maybe 5% quieter, but the ticking magnification on the firewall just had me totally perplexed. Please, please go easy on me. It turns out my pressure regulator was causing 95% of the chatter, it was basically a microphone connected by braided steel wire to both sides of the motor. I unbolted the FPR and let it hang temporarily and boom the motor is nearly silent in the cab. Happy to have found the root of the problem, slightly embarassed but at least I only spent $200 chasing this problem (different pushrods, $50 in oil/ filter).

GMCtrk

iTrader: (27)

Yeah, my regulator bolted to the firewall causes in cab noise. Not enough of an issue to bother changing on a 10 sec truck. Can't hear it with the radio on

lxcoupe

iTrader: (9)

Because race truck...