Won't I still have to balance the rotating assembly because of the new pistons and rods? So I should use a 360 flywheel, will the one that was in the truck fit in the car bellhousing?
If the pistons and rods are spec'd for a 360 and aren't super-badass race pieces, the factory balance is pretty much maintained (IMO...Some believe you should balance every rotating assembly, and they're not wrong, but what are you really after here?).
Balance is like new shoes. You can buy cleats, but if you're waltzing....
The truck wheel is mucho biggo. 143 teeth, and too many inches in diameter. There's a car flywheel for a reason.