I'm getting ready to do a frame up on my 72 GT. The truck will be used to haul my Harley and perhaps pull another car to events.I like performance. Currently it's got a 400/C6 with alot of miles. I get about 10 mpg currently. Should I rebuild the 400 with a performance build or swap to a 460 with aluminum heads, tunnel ram and dual 600s? I've got the 460, the aluminum heads, cam, tunnel ram, carbs,velocity stacks, a toploader and bellhousing. No flywheel, clutch pedal, or linkage. If this was your Ranchero what woud you do? I put about 2000-6000 mile on it a year. Some trips may be up to 3000 miles.