you might be better off getting a single 200 to 250. Lots of guys repower w/4strokes because one of their twins went bad. you might get a deal on the one that works. I repowered my grady when the shaft on one of the twin 250's broke. I traded in the working engine for like $2500. It ran fine. talk to some repower shops at the AC boat show, they might be looking to make a deal on the old trade and make some cash on the rigging.