Thread: Gas milage with fuel injection???

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Hello Everyone, I know that the words 'gas milage' & 'big block' shouldn't go in the same sentence b-u-t I was wondering if anyone had any idea how much fuel injection on a 502 crate motor would help the gas milage??? I'm referring to the Ram Jet 502 {#12499121} virses part #12496962 which is the same motor but has an 850 Holley on an aluminum dual plane virses Port Fuel Injection...... Thank You! Billl

I've driven a fuel injected 468 that got 28 mpg in a 67' El Camino. Depending on the weight of the car and the gears, I'd guess that you'll be anywhere between 10 and 20 mpg on the highway with that motor. I know some of the old carbureted big block Corvettes were able to get 17 on the highway.

I'd go so far to say that with the right transmission and rear gear, you could get as much as 22-25 MPG.

Half a thousand cubes and 20+ mpg? I call bullsh*t on that!

You have to burn a certain amount of fuel to make a certain amount of hp. You need to make a certain hp to maintain a certain speed. A bigger engine just has the capability to burn more fuel to make more hp to go faster. In the real world, it doesn't work out this simply, varying efficiencies of varying engine designs to come into play. This El Camino was geared to run 1500 rpm at 70 mph and the engine was cammed to make huge low end torque. The motor only made 300 hp at the wheels, but had well over 600 ft lbs of torque from 1500 rpm up to 4200, where the owner set the redline.

Thanks Everyone, I forgot to mention that the motor will go in a '32 Ford 3 window {weight around 2500 pounds?} with a Turbo 400 with a Ford 9" and 3.00 gears. I'm also considering a Gear Vendors Overdrive, but in that case I'll go to a lower rear end gear {numerally higher}. If I could get close to 20 {on the highway} that would be sweet. Thanks Everyone Bill

ps, LOL, one half a thousand cubes. I never looked at it from
that perspective......

I think you'll be right around 20. The car is pretty light, but not very aerodynamic. The Turbo 400 is going to burn a little extra gas. In a car that light, a th350 might be able to survive and will use a little less fuel, but who wants to take the risk? Depending on the tire height, the overdrive may not be too necessary with the low rear gear. $1700 for a GV OD is a big investment on something that might only save you a few hundred a year and that is if you drive the car a lot.

76gmc1500, a street rod isn't always about bang for the buck. There's the GEE WHIZ factor! One other note, if I had the dough, I'd use a turbo 400 with a Gear Vender! Call it bullitproof.

Thanks ... Actually I already have the Turbo 400 although its been sitting for 10 years so I will have it re-built before I use it. Its a reverse shift manual valve body built to handle more HP than I'll EVER have. Also has a trans brake with a Torque Convertor that'll handle nitrous or a blower. I was thinking about the Gear Vendors for gas milage not 'Wow factor' plus I like the 'look' with tall rear tires (30" or 31") so may be I won't need the GV. Glad you mentioned that, think I'll have the car built without it and add it later if necessary.....
Yeah the aerodynamics of a piece of plywood, huh??? $1700 for a GV??? I thought they cost more than that??? Anyway, 20 MPG sounds good Thanks again! Bill