[blykins]

When using an FT block, there are several differences. The ones you mentioned are the most prominent....machining the crank, using a different balancer, and using a different front cover.

In most cases the front covers are cast iron and are just too heavy and bulky.

The crank work will cost you quite a lot. Yes they will have to turn down the snout, regrind the keyway, and machine the flywheel flange down.

It will be cheaper to buy an aftermarket crank for your purposes. If you're not going for broke on horsepower, you wouldn't need the forged crank anyway.

As for other differences, you will need a distributor bushing placed in the block as the trucks used different sized distributors.

The blocks for the most part are beefy. There are exceptions, but you'll find webbed mains and thick cylinders in most of them.

If you ditched everything but the block, the only part you would need would be the dizzy bushing. All other parts will interchange without a hitch.