[WIDESIDE72]

Originally Posted by cst10

i have a 454 bored 0.040 over with a mild comp cam .218/.224 @. 050 lift. With 0.510 lift total, rpm air gap intake, holley 770 avenger, hei, timing 18 degrees initial and 40 degrees mechanical all in at 2800 rpm's no vacuum advance, 8.5:1 compression, turbo 350 tranny with 1800 stall, 3:08 rear gears. I get 10-12 city/hwy mpg. Buddy with same teanny rear gear with a sbc 350 about same hp/tq ratings get 14-16 mpg. I like my bb,,,don't change it out. You may regret it later.

adding vacuum advance is sure to improve your mileage.