1967 Barracuda - Slant Six (orig) or 440 Big Block? Daily Driver, Need MPG

I admire you for wanting to drive an cool old car every day. I havee to say however that you'd be better off buying a 4 cyl beater for a daily driver and wait to do the car the as a toy or hobby car. I drive a a 1996 Subaru legacy with 205k on the clock. I paid $2100 and put 58,000 on it so far. My hobby car of a 70 Duster with a 440 that runs mid 11s. Life is cheap and easy like this. Trying to drive a big block car and get good milage will be a problem.