The 230 and 250 blocks are the same,the crankshafts are different. The 230 being 3.25 and
the 250 3.53.
The crankshaft casting #'s are:
230
3788424
3820618
5743013
250
3876802
2779954
360407
I believe the last casting # for the 250 is a lighter crankshaft with less countr weights.
If you can get .080 pistons thats probably the
way to go for your boat.
The .125 bore and use of the 327 pistons is
usually for a maximum effort 250(266 cu. in.) engine.
Arnie
