Scott Ward has actually done this, so hopefully he'll come in and add some details. I can get you started.
The 235 bellhousing will NOT bolt to your V-8. The V-8 bellhousing will bolt to the SM420. The V-8 bellhousing will NOT bolt to the '49 crossmember, though if you can swap to a '54 crossmember the V-8 bellhousing will bolt to that.
I'd use the V-8 flywheel because you can be sure the ring gear is going to work with your V-8 starter.
