Here goes: I've become very well versed on the BOP/R 215/3500 aluminum V8. I have a jetfire turbo setup I'm putting into a Pontiac tempest. But that's not the discussion. This is the part that I need a group of Rodders on: in my purchases for parts over the last few years I have found a few oddities. Long story short I have a 6 bolt pattern Oldsmobile 215 that someone sent out for freshening plaining and Buick 300 crank installing. So. How the hell am I supposed to hook that up to a roto hydromatic 5? The slim Jim? With a machined plate and sprag clutch plate with splines to drive the pump/tranny? The 300 crank shares the 300 & up Buick bolt pattern on the crank. The block has its very own transmission pattern for twin path dual turbine, roto Hydro 5, & tempest rope drive bellhousings as well as rovers. I have a set of 300 Buick heads and the drilled 6th hole concerns me also with the 5 bolt Buick heads.