I have a mildly built 460 and it's knocking and i don't know why. i pulled the roller rockers and pushrods and there's nothing wrong with them. I'm not sure what else to check because the motor only has 15,000 miles and the only problem i've ever had with it was a knocking from the pushrods but that was due to defective pushrods which were replaced about 5,000 miles ago.

 

If the knocking comes and goes with throttle position (changes sound, pitch etc..) then it is most likely rod knock. If the knocking seems just to vary based on RPM only, regardless of throttle position, then it is your main bearings likely.

Pull the valve covers and run the motor. Check for valves snapping shut.

 

i'm sure the knocking isn't from the rotating assembly at all by listening to it. when u start it it takes a few seconds to start knocking and then its steady and the knocking speeds up with the rpm's.

 

Has it got a stick or automatic transmission behind it ????.

If its a C6, set the parking brake, crawl up under it & pull the inspection plate at the bottom of the bell housing.
Look at the back side of the flex plate, if it has little streaks running from the center, bout willing to bet the flex plate is busted.
Those streaks are little metal shavings slung out from the center from all the shifting between the plate & the end of the crank.

If that is the problem, the plate busted, its heavy duty flex plate time.

Oh, dont ask a Chevy guy about it or you'll get,,, those D ford 460s the cranks aint worth a crap.
Got new for them big boys, that 460 cranks bigger than a 454 crank.
Neil

 

I'm having a similar problem and I think I figured out the polynuts on the H/S roller rockers are working loose and causing the chatter. I've reset the valve lash 2 times this week, don't know how to solve problem without overtighting and messing up valve lash with hydrulic lifters
John