Small Block & Big Block Chevy Specific - needing 2 pice rear main SBC badley

hey guys, needing some help on my boat project, replaceing the block on my 85' sea ray I'm looking for either a 2 pice rear main 350 that will cleane up standard, or a drive coupler for a mercruiser alpha 1 in a 1 pice rear main bolt pattern. i have a good 1 pice block and crank if need be. gotta have her running by july lol. thank y'all for any info or advice

I have a Bow Tie block that is for a one piece seal with an adapter and a two piece seal and crank. What ever mine is it leaks, but by now there are better ones.

Read this:

http://www.circletrack.com/enginetech/ctrp_0712_rear_main_seal/viewall.html

Al 95 Z28