Huh? You're obviously new to the marque. There's a 6-bolt crank (6x bolts in the flywheel) that is all Imperial and wider journal's, or there's the later 74+ crossover metric + Imperial 8-bolt crank. The latter can take the B21 pistons. The 6-bolt is more common, but reputedly suffered from the very remote chance of cracking a gudgeon pin. I suspect that failure was due to uncontrolled detonation.
Either one will do what you want. Either one has the potential, with a lot of head porting, to make decent power numbers.
