87's have one bolt holding the upper A-arm in place, 88-90's have two bolts holding the upper A-arm to the frame.

Twin? LOLWUT?

Warmeck to answer the part about jetting,  race fuel or avgas are consistent year-round.   While pump gas can vary.

I run race fuel for the exact reason motorgeek stated.  For both consistency and to protect my expensive motor from detonation.