Remember the 292 is a couple inches taller than the 230 when doing your height calculations. I put a 292 in a 66 Chevy II and had to use a very thin air filter element to clear the stock hood.
The 200R4 should be fine behind the 292, but with the 3:08s, it may be too much in OD. Maybe something like a 3:42 would be better; definitely more fun! Something like a Comp 260 or a Clifford 264 would probably be a good cam for what you are planning.
As far as motor mounts are concerned, two things to think about. Are you using a mechanical fuel pump and will you ever want to go back to the smaller motor or a V? You will like need to move the frame mount to clear the fuel pump, but if you want to easily swap to different motors you will want to modify the mount on the motor.
Good luck on your 64!
