Jack,
I did the same thing on my '55 210 4 door and drove it daily for years. I used the stock v-8 front mount kit (it uses the other two holes in the front cross member) and a side mount kit for the turbo 350 (later a 200 4r with the same kit) and it was fine. I out about 20k miles on it and got over 20mpg with the 200 4r. The kits that I used were from Danchuk for a small block / turbo 350.
My car was a p/g so it had 3.55 rear gears which worked good with both trannies. If your car was a stick, I think it has 4.11 gears - you might check. That might be a bit much for a t-350, might just start with a 200 4r from the start. Nice thing about the 200 4r is that it is the same length as a t-350 and you can use the stock drive shaft.
You will have to make a new exhaust system unless you have a muffler shop build a Y pipe to join into the stock exhaust (but WHY do that????).
I used, and still use, the stock 6-cyl style radiator with the built in trans cooler. You can get a replacement for yours with the cooler or use an external cooler with your stock rad.
Other than removing the clutch pedal ( pull the assembly and remove the pedal or sell/trade the assembly with someone who wants to convert to a stick) and figuring out a shifter (floor - so you don't have to change the column) that should be about it.
Good luck, and have fun!
Later,
Mike