Turning the crank's same as for a 318 or 340. Might be about as much as a new 4" crank on the high end. Not uncommon for 360 cranks to be too worn to get away with a turn-down they could run in a 360. The pistons though- that's where it'd cost.
So, I've been told. I haven't priced out machining a crank, but I don't think you can get away with a 4" stroke in a 273 without major bore surgery. And I agree, pistons would be the high dollar item. We'll see what condition my engine is in when it comes back. With a 3.54" stroke and stock bore, you're only running 292 ci. The engine only had 8.8:1 compression, stock. With the 360 heads having larger chambers I'd imagine compression would go down to low 8:1 to high 7:1 on the stock stroke. Maybe the stock pistons with the larger stroke and bigger heads would be happy enough to allow everything to clear and compression to be reasonable?
