12 mpg sound right for 351 crate?

[DAVID GAGNARD]

I have a 351-W, about 350 flywheel hp in a 65 Fastback with a Tremec 5 speed and 3.25 rear gears....Holley 600 double pumper, Eldelbrock daul plane intake.....
Cruising on the interstate @ 75 mph (2000rpms), I get 23 mpg, never checked it around town..........last trip to Florida, I put a little over 750 miles for the round trip and averaged 22.3 for the trip.....

I think your mileage is a little low, don't care for your carb either........with your set-up, I would expect in the 18-20 mpg range for highway cruising........

David

[Michael P. Wole]

I am about to embark on the Hot Rod Power Tour...will be a little over 2300 mile trip for me. Will check my mileage and report back. I am anticipating around 15 mpg.Just built a new 351w +.030, World heads, Comp cam, 650 dp Holly on a Stealth manifold, March underdrive pullies, MSD ign, coil and dist(mech). Dont't know HP yet, will get it dyno'd on the tour or when I get back. I have a G-tech(accelorometer) and first run Sunday nite was a 13.009 @ 111 mph. That was with my 315# son-in-law on board and smoked the tires for first 100 feet. I dont know how accurate the G-tech is but is a neat toy.

[Frank Messina]

Your mileage seems low with that engine. But with the 3.73 rear gears, spending a lot of time in fourth gear will kill mileage fast. Are you running vacuum advance? If not that's another thing that will hurt gas mileage. Hook up the cannister on the distributor to a manifold vacuum source on the carb. This will give about 7° additional advance at off idle and part throttle cruise. ( it's adjustable with a 3/32 Allen wrench) Throttle response will go up along with a nice bump in mileage. Contrary to what else you hear, don't bother using the timed port on the carb. That's a no performance smog hookup. HTH

[Dwight]

5.0 stroked to 354 fuel injected 323 rwhp 375 rwtq,
3:55 in a 8.8 with 25 1/4" tires TKO 600. 70 mph I doing about 2000 rpm
Last year trip to the London Cobra Show, 1350 miles, I got 21.8 mpg

Dwight