Ok... I just bought a '91 350 bored .40 over, you can see more of the specs below... The car has two known issue, one, a vaccum leak on the intake, which I have posted about in the TBI (yeah, I know, but it's what it is...) Forum, the second of which is a or multiple bent pushrods. The motor has very few miles on it, so I'm guessing it was put back together with pushrods that were too weak to handle the cam, the revs that the car can produce or the like. So, my question is, what type of pushrods should I use? Would you expect them to be the same length as the stock pushrods? Thanks in advance for your help... See below if you're interested in what this car has.

Here are some of the features of the Motor:

- All Bore 383 w/TBI (350 bored .40 over) Forged TRW Pistons, rods, and Crank, New 1.6 Rockers, Balanced Rotating Assembly with high volume oil pump.
- Ported and Polished Vortech Street Heads
- Mild Cam ("Mild cam 218 Duration 246Lift or something like that" is what I was told)
- 3:42 with Auborn Positrac built at Chevy dealer.
- Flowtech Equal length headers w/3" cat back & flowtech muffler.
- Dry NoS system.. Plate/ 150 non-interchangable shot. 120hp. Bottle is full
- 700R4 4spd Auto Tranny
- Converter is set at 2550 Stall (sort of an odd number to me, but that's what it is...)

 

Bent pushrods may be from too stiff springs, low quality pushroda (not usually) or valves too tight.

 

Vortec heads + 1.6 rockers which produce lift greater than .475 or so = retainers hit the top of the valve guides ??

Look at the top of the guides on one of the places that bent a push rod. I'd bet you'll see signs of interference.

You might be able to cure it with .050" offset keepers and .050" spring shims; but that's sort of rigging it. You might also have to replace the retainers to get the special keepers, which might by themselves cure the problem, or they might make it worse.