[L31chevy]

I'm condsiering building either a 350 EFI SBC or a 454 EFI BBC. My question is, is that considering I go mild on the build up's what will my Mpg be City/Hwy for both of these engines? I say this because if there's not a real big difference in the fuel consumed I'll definitely go with the BBC, if not I'll go with the SBC. If this helps out, I do street more than the strip...

[78 monte]

I think whats gonna make the differance would be car weight,reargears,cam selection.I heavy car would proll have worse city milage w/ a small block cause of less Torque.A big rear gear could make good city milage but kill highway cause of the high rpm you'll turn,so I would think with a BB you'll be using more gas to maintain a higher rpm..And the oposite for small gears cause they take more torque to move the car off the stop light,which is were the big block would prolly have better city. .And also selecting a cam thats perfect for your setup.They evan make cams with gas milage in mind.
And of course your foot too.

[ October 13, 2002: Message edited by: 78 monte ]</p>

[4 Jaw Chuck]

You'll probably find little difference between the two, maybe 1 or two miles per gallon especially in a light car. In a heavy car you might even get better mileage with the big block. As was said it all depends on gearing and weight.