409/409

What kind of gas mileage can I expect from a 427/390 vs 427/425 with 3.36 gears? What are you big block guys getting?
Thanks

JohnZ

If you really care, you bought the wrong car..

Nowhere Man

That's a good one John . But if he keeps off the back two barrels he should get around 11-13 mpg. But who really cares

66 Double B

8 mpg while dodging potholes. 10 on a rare maintained road in Jersey.

OldKarz

I get 7-10 on a good day...... I do not care, I fill it up and run it out. If I had that rear, I bet I would get a couple more mpg.

big block ken

i owned a '66 427/425 with factory 4:11 gears and it sucked - literally! Probably @8 mpg. But when can you ever drive a car like that with economy in mind?! My current '66 427/390 has 3:36 gears and I have to say that it does very well. I'm guessing around 12 mpg. Hmm..now I'm thinking of installing one of those magic magnetic fuel filters in line to increase it to 24 mpg!

StrayDog

Have owned my BB almost 20 years, w 3.08 got 16 HWY , may bee 13 city , switched to 370 ( more fun ) approx 10 year ago city 10 maybe.... but its a rocket , have gone back & forth with a double pumper yikes side exhaust & a rocket ...think of it this way what difference duz it make maybe, as u drive it 2k miles a year its insignificant if it gets sh#ty mileage its about the

Amendum had a 64 SS 409 /425 , back in the day , woof

The dog woof

carlton

I had a 66 390 HP with 308,s and got a constant 18-19 MPG in the late 60,s when there was better gas and I had a 40 mile commute to work on 55 mph roads. With the gas we have now and 3:36 gears on the same type of road. I would expect 15-16 with easy driving.

Joe Inama

Not sure, when tank is empty ,I fill it.

ptjsk

That's got to be near impossible!!!

dugsgms74

13 mpg average on my 390hp w/ 3.70 gears.

LT1driver

back in 70-71 my 435 coupe with 3.55 gears got 15 mpg on hwy at 70 and in town never checked it....was young guy with first vette and in college, you do the math....lol I agree with JohnZ however

SonnyAK

I can pretty much count on averaging 10mpg with my '66 425hp car

DansYellow66

It will probably make a big difference between mpg on a trip or commute with steady driving - versus mpg for typical back it out in the driveway to warm it up a few minutes, drive down to the local grill or drive-in, open it up a little returning home, let it idle a few minutes to check everything underhood before shutting off.

I have 4.11 gears so my mileage won't help you but it's pretty bad considering my drives are pretty much of the latter type.

GUSTO14

Drove our sons 427 from Pensacola, Florida to eastern NC a few years back and averaged 32 mpg. Mostly 65-70 mph on the interstate and 55-60 on other roads.

Of course it was a 505 hp 427, no wimpy 390. I think the secret to better mileage is just more horsepower!

Good luck... GUSTO

427/42566 coup

Can't really answer that question my foot's in it most of the time