With $4 gas, what do you get for mileage??????

408 stroker with 727 + 3000 stall in 4.10:
Using Holley DBl Pmp 750 = 8 mpg hwy @ 55mph (running rich)
Using Carter 600 Vac Sec = 14.1 mpg hwy @ 55 mph

a BIG difference with nothing more than a carb change. Best of 13.42 with Carter, and 12.88 with holley. The holley probably has more HP with tuning and jetting down. That and timing and I'm hoping for under 12:5 with traction limited street tires.

Would like to switch to 3:55 or 3:73' to help cruisability and mpg, while not hurting ET too much.

Oh yeah, It has 9.6:1 compression with aluminum heads, and I am running 89 octane (mid-grade!)