I wouldn't worry about a cast 360 crank at 675hp... mine has a cast crank in it (has never even been turned) and makes somewhere in the 850hp range.

Obviously there is some difference between the blower and the turbo... but if mine will make 850hp, your's can make 675hp.

If you're talking 100% stock short block... you'd be pushing it REAL hard to go to 675hp. I'd say 500~550hp on cast pistons with a good tune is about the limit (we're just about finished with a 100% stock magnum 318 with a 69mm turbo going in a Demon... so we'll see).

If you're talking about main studs, rod bolts, and forged pistons... you should be able to make 675hp as long as the tuneup is good, and you have the proper fuel for the boost numbers you're talking about.

Mine with a stock 1/2 filled block, stock crank, main studs, ARP rod bolts, and off the shelf forged pistons made over 700hp. That was the point I put good rods and better pistons in it.

My guess is you'd be able to max that blower with a good intercooler and good fuel before it ever broke the block. Especially if it's partial filled.