Hello everyone, this is going to be long so please bear with me...

I recently built a 470 stroker using 440source aluminum heads and a hughes hyd. flat-tappet camshaft. Initially I had the 440source rocker arms and shafts on it, but because uneasy about the quality of those rockers so I decided to switch to the Crane Gold roller tip rockers.

I'm glad I did too because the "super heavy duty" shafts they sold me had been eaten alive by the roller bearings in their rockers. there were grooves worn into the shafts from the bearings that you could hang a fingernail on.

So I decided to use the stock shafts that I pulled off my 383 magnum when I switched to the new Crane gold rockers because the stock shafts were in really good shape. I checked to make sure I had the shafts installed right-side-up so they are oiling properly.

As per the Hughes instructions, I initially set preload at .08 on all the rockers.

When I start the engine from being cold it runs awesome, idles great, and the valvetrain is very quiet. However, when it reaches operating temperature (approx. 160-200 degrees) the valvetrain starts clattering terribly and sounds like an engine with no oil pressure. I have plenty of oil pressure.(40psi hot at idle) the idles also gradually accelerates from 600rpm cold to 1000 rpm hot once the valvetrain starts sounding like a diesel.

I tried adjusting the preload down to .04 because I'd heard that too much preload could cause noise when it got hot but it didnt help at all. Any suggestions as to what could be the problem?

the specs are:
470 shortblock, 10.0:1 compression.
440 source ported heads
Hughes camshaft 242/246 duration, .555/.569 lift
1.6:1 crane gold roller rockers.
Comp lifters
comp 3/8" pushrods

Any help would be greatly appreciated... I'm pulling my hair out and I'm afraid I might be doing damage to the cam if the valvetrain is that noisy...

Thanks!