just wondering what may have happen to engine this is what I was told happened fresh from engine builder with 50 runs on it oil change and went thru valves 30 runs before this happened 582ci on dragster has a dual fuel system on it shut off after burnout was spinning fine never got it started when I pulled VC two push rods broken on cyl. 6 & 5 both intake push rods broken 3rd cyl on both sides of engine its got to come to pieces but was wondering what might have caused this to happen

Check for coil bind on your valve springs. Excessive or tight lash, weak or broken spring. Possibly even piston to valve clearance.

check spring pressure every time you check lash.

I've tagged an exhaust valve valve during an over exuberant burnout, but it only bent the valve slightly.

Might also, check rocker isn't hitting valve retainer..

Dave

check everything but my bet is piston to valve clearance issue. Too much advance on the cam, tight on the intake p/v clearance.

With 50 passes on it I would have thought it would have tagged a valve before now also with it being intake push rods I'm not saying it couldn't happen but valve is chasing piston. What type of push rods are you running, and what is the lift approximately ?

I had 3 pushrods from a very reputable manufacturer break right where the insert was pressed in. No clearance issues at all. Never came near a piston. All at the lifter end of the pushrod. The press distortion had over stressed the tubing and they failed so cleanly that they looked like they had been severed with a razor blade.

Strange things happen.

If these are new pushrods rather than previously run, it might be worth checking the hardness compared to the earlier set. I'm not a big block guy but if they are angled and hardened too much it might have caused an issue. Just a thought.