Larger tires on the rear are generally for better traction if running a hot motor,if not then just for the "old school" cool look.
I have 275 on the rear and 215 on the front of my 72 Duster.
99 Toyota Avalon (my dd)
08 Toyota Avalon (wife's dd)
72 Duster 440
72 Chrysler Newport 400
08 Pontiac Grand Prix Gxp- for sale
01 Mustang GT vert- for sale
82 Chevy C10 shortbed 454
75 Chrysler Newport 440 parts car
73 Chrysler New Yorker 440 parts car.
If you want a little more hp and tq put some good headers on it. Be prepared to tune the carb a little more. Tune the distributor as well if you haven't already.
Headers is a he said she said argument. Some like them and some don't. It is up to you.
The 1 3/4 headers should be fine for all but the wildest applications.
I have 2 " and mine rattle off the pass side of the engine bay and one torsion bar (aftermarket 1" bars).
Not bad but it does hit.
I will take 16hp and 22tq every day of the week. And that is just peak. I would imagine gains would be larger in most cases across the curve and hold on longer after peak as well.
Beautiful and ambitious project. Is it a completed running and driving car ?
If more work is needed what would that be?
More details on transmission,rear end,etc.
I am not in the market but I bet it would be a handful and surprise many a fellow.