Reply to "What cleveland block to use for HP engine?"

CK they do split, I've seen 'em, and this was back in the era before affordable stroker cranks & the prevalence of roller cams, which may have been part of the problem.

Look at it from this angle: The Cleveland heads are capable of supporting tremendous bhp, but to make eqivalent bhp with a 351 cubic inch motor reuqires the owner to run higher revs than with a 400 cubic inch stroker. Also, in the seventies, a cam with 0.600" + lift was a full race cam, again, high rpm stuff.

so folks were twisting that crank pretty fast, probably should have been using internally balanced high buck racing cranks, but the cast iron crank was so durable, most guys just ran it instead, external balance and all.

Finally I'll point out that when an engine grenades, nobody ever mentions whether or not the reciprocating assembly had been dynamically balanced, or whether or not the fuel & ignition had been dialed in on a dyno. It doesn't take much at high bhp and high rpm to shake a motor apart.

On boring cylinders, the issue isn't hitting water jacket with a 0.030" overbore, the issue is the cylinder walls getting thinner than a universally accepted minimum for a cast iron cylinder wall, which is 0.120" thickness on the thrust surfaces and 0.080" thickness on the non-thrust walls. Flexing and heat cycling of the cylinder walls is exacerbated when the walls are made thinner by boring AND by higher bhp and rpm levels.

your friend on the DTBB