Sorry I didn't notice the post sooner, I've been out on the coast.
The flywheel fits in the bell housing just fine. The tricky part is making the clutch and pressure plate fit while still having enough throw in the fork to engage and disengage. I had to change the throwout bearing. I can't remember if it was too short and I put a long one on, or too long and I put a short one on, but it was the opposite of what it came with. I had a couple of extra 216 bellhousings and some 250 clutch parts on hand. I think I might also have changed the stud that the fork pivots on, but if I did I just swapped them between bellhousings.
As far as the ring gear, I was not in the shop when my machinist did the work. He said he just used his brake lathe and measured and pressed on the ring gear, no heat. It looks just like the factory did it. I heated the 216 gear off the old flywheel by heating the whole thing up in a propane bbq grill for about an hour and tapped it off with a drift and a framing hammer. It was dang hot but it came off easy enough.
If you have the right press anvils you can press ring gears off and on to the flywheel, but I like to do it with a gas grill. You can heat the whole assembly to remove, or just the ring gear to install. You want some tongs for handling. You can also do it with a weedburner torch but the grill is easier.
If you want to use the same rear mounts on the bellhousing you have to use a pre-'54, after that the mounts don't fit.
You should be able to use a 235 foot stomp starter from '55-57 with a 216 bellhousing. ( I don't know when they switched to solenoid). The only differance in starters is that the teeth change depending on whether they are 6 or 12 volts, they both bolt up. I used the 216 starter because I wanted to be able to keep the truck 6V, although I ended up converting to 12 anyway because I needed the electric fan.
