Back in the '90s when I decided to get my bus a more powerful engine than the stock 2bbl 327, the first thing I did was look at the Chevy/GMC medium duties that all the wrecking yards had at the time. Every one of the 427s had the same spun main bearings and valve train issues that the '70s BBC pass car engines had. And because it was a BBC, a buildable core was $2500 without the heads.. so I thought, oooh I could sign up for more bottom end issues, valvetrain issues, oil usage, and all the other old school big block foibles.. or just go through one of the Cadillac V8s of which I had a yard full. Designed from the start to be 500cid (actually, was designed to be increased to 600, but then the gas crunch hit) and to run for hours without trauma at exactly the RPM range typically encountered in a bigger rig. Most of 600lbs/ft by 2000RPM, and it turned out not to mind having a manual gearbox behind it.
I had to have the Chevy flywheel machined to match the Cadi crank, but once I did I was able to keep the huge, bellhousing mounted original starter. The flywheel face to back of block distance turned out to be the same, I think it's a GM standard from 1948 onwards along with the guide pins also being spaced the same throughout divisions. The factory installation even had a steel adapter plate from Chevy block to big round 2 ton bellhousing-I had only to drill a couple of holes! Once done, the adapter plate bolted to the back of the block and then I could bolt that assembly to the bellhousing.
I sure was grateful for the hydraulic clutch! That made things so much easier versus having to recreate the ball stud that a Chevy block would have had a hole for.
