i have a 85 z28 500hp 400sbc tricked 700r4 full ssm kit moser 12 bolt with 4.30,s. so far i have broken 3 rotors in 2 superior tough pumps an one superior magnum pump. im using a tci 3800 stall converter. i break them in 3-4 runs in 12s im reving to 6300 msd chip. we are now wondering if the stock external flex plate is to blame. any ideas or sim incidents, help!

Is this the same one I have responded directly to?

Anyway, what does the Rotor material look like? Is it "shiny" or dark? Is there any ID mark on it?

Hey Leo yeah same one black rotor, we are now considering making a cast an making a cast iron rotor, any thoughts on that . i still think it was the flex plate causing the problems, i have installled a B&M sfi plate much thicker an stronger. but my friend that owns the tranny shop isnt convinced an is still looking for a better pump. what would use in this situation?

You may be right about the Flex Plate. I asked about the Rotor because I know for fact there are some cheap aftermarket Rotors out there. Is there any chance that it sucked air for an instant? The off-on pressure with a BIG spike could have done that too.

sounds to me like you need some offset dowel pins....