Hmm, crap, because I found a shop that apparently makes adaptors for 1-2 piece rear seals. Hopefully those large journal 283 cranks are magically common every day finds... Xfingers.

Are you sure the L99 3" has small journals?

That sounds like a mean car Scooter. I'd love to hit low 12s, how streetable is yours? Pump gas? Daily-driveable? Stall setup?