K blocks have stronger connecting rods, but were still liable to throwing rods because of crankshaft flex (usually piston #1 if I recall). In either 1990 or 1991 Volvo went to larger crankshaft bearing surfaces and I believe they added a couple bearings (?) for the B230, as well as keeping the larger rods....this is a bullet proof engine. In 1994 they added piston oil cooling jets on the underside of the pistons....this is the engine to get. I'm a little hazy, it's been awhile.

P.S.

I wouldn't worry about your con rods unless you're planning on running over 250 hp turbocharged....otherwise, things should be pretty solid.