Looking at the bottom line on your post, I would guess that the B230 you are talking about is an 87? This would be one of the motors with the weak rods. Your best bet would be to look for a B23ET or FT motor. This motor has the better forged crank as oppposed to the later cast crank, and has the thicker rods. The other option is to get a slightly later motor - the 'K' series B230 (starting in 88??) still has the later cast crank, but does have stronger rods and will hold up better to higher power levels. There were also several changes in the 1990 model year with fuel system, turbo, manifolds, etc. although the basic block is the same. I would look for a 90 - 92 B230FT donor and consider taking the entire fuel system, etc. Also, if you can find one of these with an M46, the OD is a stronger unit than the earlier ones - higher working pressures and you do not have to worry about having the OD engaged under full boost. The ones prior to 90 had a boost pressure switch that automatically cut out the OD at full boost to prevent slippage and damage.