Big Block?
Thread Starter
Racer
Joined: May 2004
Posts: 315
Likes: 0
From: North Richland Hills TX
Big Block?
I currently own a 350 putting out 420 HP in my '80. I get anywhere from 12-14 MPG now...idle smoothly at 800, still streetable but mainly a weekend cruiser. I've come across a great on a BB 502.
Curious: what kind of MPG do all you BB owners out there get? Still streetable?
Thanks
Curious: what kind of MPG do all you BB owners out there get? Still streetable?
Thanks
Drifting
Joined: May 2002
Posts: 1,546
Likes: 5
From: Sacramento California
My 427, (mildly built, cam, headers, 800cfm) gets around 5-6 mpg, If your small block is making that kind of HP and milage, I would leave it alone.
My 2 cents
(I should mention that it has 411 gears and a M22)
My 2 cents
(I should mention that it has 411 gears and a M22)
Last edited by 427basketcase; Dec 29, 2008 at 01:01 PM.
Senior Member since 1492
Joined: Aug 2000
Posts: 87,971
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From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
I currently own a 350 putting out 420 HP in my '80. I get anywhere from 12-14 MPG now...idle smoothly at 800, still streetable but mainly a weekend cruiser. I've come across a great on a BB 502.
Curious: what kind of MPG do all you BB owners out there get? Still streetable?
Thanks
Curious: what kind of MPG do all you BB owners out there get? Still streetable?
Thanks
Le Mans Master
Joined: Nov 2008
Posts: 5,691
Likes: 12
From: columbus oh
crate 454 from gm in my 66 gets an honest 12=13 in town and 15 on the road and even better in od with a keisler. i have a 336 rear. 425 horse with a 750 holley hp carb. it did a little better with a 750 street avenger carb but i have better performance with the double pumper...........i run REGULAR gas with 8-3/4 compression and true 500 lbs torque at 3200 rpm!
Last edited by midyearvette; Dec 29, 2008 at 12:10 PM.
Intermediate
Joined: Sep 2008
Posts: 36
Likes: 0
From: Haymarket VA
I currently own a 350 putting out 420 HP in my '80. I get anywhere from 12-14 MPG now...idle smoothly at 800, still streetable but mainly a weekend cruiser. I've come across a great on a BB 502.
Curious: what kind of MPG do all you BB owners out there get? Still streetable?
Thanks
Curious: what kind of MPG do all you BB owners out there get? Still streetable?
Thanks
I've got an LS-5 (BB 454) daily driver mostly stock with a 750cfm edelbrock, edelbrock intake mild cam and side exhaust.
I have a 3.55 rear on 27" tall rears 4sp and get 12 with mostly highway driving. I do run it hard passing accelerating and such and still get 12. My biggest complaint is I can't get more gas in the tank so I can drive farther.
I'm running regular with my 8.5:1 by the way and the car is extremely streetable!!! I own a few of 327/350 sorts, for a performance car, I personally am not going to go with anything else but a big block from now on if I want to balance street use and performance.
jeff
Last edited by JOs71Corvette; Dec 29, 2008 at 12:38 PM.
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Melting Slicks
Joined: Mar 2007
Posts: 2,100
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From: Frederick Maryland
'69 427/435 bored .030 over with L88 cam and 4.11 rear = 6mpg no matter how it's driven...easy or fast. Maybe 125 miles to a tank of 93 octane.
For your car...if it ain't broken, don't fix it. If the 502 is a great deal, buy it and use it for another car or resell it for a profit.
For your car...if it ain't broken, don't fix it. If the 502 is a great deal, buy it and use it for another car or resell it for a profit.
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From: Cape Cod, Mass.
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My 68 427/390 with a Turbo 400 and a 3:08 rear end isn't bad at all. About 17mpg on the highway and 10 around town. If you stay out of those coke can sized secondaries and cruise on the small primaries it isn't much worse than my small block cars.
Burning Brakes
Joined: Oct 2007
Posts: 946
Likes: 0
From: Lake Geneva WI
Agreed, I see about 190hp if that and achieve similar MPG. I'd stick with that former.