so i finely get me 400 running, i'm breaking in the cam, i hear some lifter noise,
shut the thing down, remove the vove covers and find that i have bent one of the intake push rods, so the question is: what caused this to happen?

 

Did you change the valve springs? Can they handle the amount of lift your cam provides? Is it possible it got bent when installing? Just throwing out ideas.

 

Improper valvetrain geometry which can include; coil bind, wrong pushrod length, to much lift for rocker arm, bent valve, improper machine work, improper keepers, wrong shims, etc. The valve train on the 335 and 385 series engines is not simply a bolt together affair. Clearances must be carefully checked. Unfortunately you may also have ruined the cam which means cam and lifter replacement.

 

I wonder if the valves hit the piston tops. He said that the intake valves had the bent pushrods. If there was a little too much lift on the intakes lobes, all the intake pushrods would bend.

 

I had this, was from the machine shop installing the intake spring on an exhaust valve,or rotator was put on an intake valve, can't recall, was OK with stock cam, but limited required lift with the RV cam. I had the heads pulled and all the old springs were replaced, I've not had the problem since it was put back on assembled correctly.