pressure plate experts

Yeah, AutoZone heavy duty LOL. I just put a regular AutoZone heavy duty diaphragm clutch in the duster years ago when I was getting it going. It worked great four years at the Dragstrip taking my 318 car into the high 13's with slicks and everything. It wasn't until I had the new Stroker motor in the car and that took another year for the clutch to start slipping at the Dragstrip.
So....after reading this thread, can anybody tell me where to buy a 273 pressure plate that would be correct with first installation? I am having some issues with my clutch not completely disengaging (most notably when shifting to reverse).
Great reading...thanks FABO members