What would a fuel injected 454(or any big block) get as far as gas mileage

My efi 383 would get 17 on the highway with the 4speed and 3.08 rearend (probably 420ish hp, Sportsman 2 heads). I bet it gets close to 19-20 with the 5 speed, .68 o/d but I never checked it.

I've been wondering the samething!

Mine hit 20.7 mpg 2 tanks in a row going to the cruise in a few years ago.

I've heard of low 20s being kinda normal, on the highway. Of course if you lighten the car, make it more aerodynamic in some form, and use an overdrive and lower rear gears you can get that pretty easily.

My '69 427/435 gets a whopping 6 mpg...anything would be an improvement. Two things keep me from converting it...it's all numbers matching and correct, plus I don't believe anyone makes a fuel injection system for the rectangular port heads.

I was going to change it to a 5-speed but a sudden hospital stay made me rethink where the dollars available were going to be spent.

Rochester products can probably make ya one.

Geez!!!! What kind of gears are you running?!? I have heard that the Tri-powers are more fuel efficient that a 4 barrel.

what kind of gears are ya running? do you have an overdrive?

Check his signature frstr90.

http://www.corvetteforum.net/c3/zwed...te/71vette.htm

The car runs 4.11 gears and it has an L88 camshaft...it's power band is from 4400-7000 rpm's. To say the least it's a pretty cranky engine. While it naturally has plenty of torque, when you pass 4000 rpm's you really feel a kick in the pants as it begins breathing.

As I said...I was going to install a 5-speed but an unexpected stay in the hospital and the bills from that made me change those plans.

hahah.. well that explains it! I am feeling a little jealous right now!

p.s. With a 5spd. don't ya think ya might be lugging that engine a little too much?

My intent with a 5-speed was less improving the fuel economy as I doubt it would be a whole lot, though it would have helped...and it never would have paid for itself for as little as I drive it. I was more concerned about keeping the rpm's and engine wear down.

I had thought about a 6-speed, but that would have required cutting the trans tunnel. I'm not about to do that since it's all in great condition with the original block, heads, intake, carbs, etc. No point in hurting the value, but any changes I have made aren't something that can't be readily returned to original...like the stereo/CD player replacing the original AM/FM and the MSD 6A hidden behind the passenger side of the dash.

That engine has so much torque it really doesn't need 1st and 2nd gears. 3rd and 4th is all it needs except trying to start on a steep incline. I've named it "Stumpy" since I think it could pull tree stumps.

Some people that have put the 5 spd, also had to cut the trans tunnel. You've got a great car! For what you say, you don't drive it much. So I don't really see the need for the 5 spd. I d say keep it the way it is.

zwede, I looked at you set up thanks to kalway... It looks quite nice! If you were to do it all over again, would you go with Holley EFI??