If I were to change out the 4-barrel carb on my 460 to a 2-barrel carb. Would there be any significant increase in MPG? If so, could anyone recommend what 2-barrel carb would be compatible with my engine?

Thanks very much for any assistance, advice and/or recommendations anyone may be willing to offer!

75 SuperCab

 

I get better mileage out of a 4v because I can keep my foot out of it.

The primaries of 4v are smaller than the 2v thus less fuel is used.

You could also find a square bore intake and get even smaller primaries :0

How come you did post in the fuel delivery forum ? *grin*

 

HOW?! Ever since I went 4 barrel I find it impossible to stay out of 'em. Hopefully this will wear off, but I doubt it .

 

I agree. My '73 390 got 10 mpg (highway 65mph) with stock 2v. Switched to a Edelbrock 4v and iron intake and now it gets 12mpg - when I'm nice. But I tend to throttle it more, just to 'feel the power' and 'hear the pipes growl', that tends to hurt the mileage...

There have been discussions in the distant past about guys running 460's with lincoln spreadbore carbs (very similar to a quadrajet) getting very good mileage 16-18mpg - if I remember correctly. Might try searching past threads.

 

Theres a lot more to good gas mileage than just the number of barrels in a carb.... a clean fuel filter...the right air mixture... good clean plugs and proper timing are all essential to getting good gas mileage. Basically the vehilce must be in tip top mechanical condition to see the optimal gas mileage.

You can get comperable gas mileage with either if you keep from mashing the throttle through the floor boards. Not to mention the fact that you will obviously see an improvement all around if you replace a carb thats out of tune with one that isnt.

For all of the work and $$ it would take to replace any carb the better solution is to rebuild it...give the truck a tune up and keep the foot light on the pedal.
-Chris

 

a four barrel only acts as a two barrel when your light on the pedal. stay off the gas and youll do better on gas but still have the power of the 4b when you need it.

 

I am getting about 10-12 MPG with my 79 400, 2v, 4 speed, 33's, stock motor as far as I know. What is a good intake, 4 bbl combo you all have luck with?

 

BTW, I live in Ohio, so smog control isn't really any issue here.

 

I am contemplating an Edlebrock Performer Intake and Carb for my 429.

Right now it's all 70 cast iron with Ford carb.

 

It's possible to find a 429 2bbl intake (or just use an adapter), but I wouldn't bother.

For 'economy' carbs, I've had good luck with Quadrajets of all things, and the old 650 Holley Spreadbores (which are a pain to tune...). I get the absolute best out of the old 4100s.

Some people got into the Carter AFBs/Edelbrock carbs and claim they do well. Never had much luck out of either nor could I get them to run like I can a Holley.

What carb do you have on your engine now? If you have a double pumper or something, no wonder.

 

Pretty much a stock engine, Dennis? If so, go for it. I've always considered the Performer stuff stock replacement parts. Good for the average street car/4x4.

 

Yeh, a "Street Car named desire"

I'm looking for "Lighter" with same performance or better from stock.

Before installing my engine I ported & polished the intake and a little of the heads as time was of the essence back then.
I run the 4100.

I also contemplated getting the Carter AFB a great carb.

 

I'd just stick with the 4100 then, which was the best street carb ever made as far as I'm concerned. Pretty easy to tune as well. Never was much of a AFB/Performer fan. Never really got into the metering rod thing. It's just so much easier for me to tune a Holley (or Autolite, or whatever) then one of those.

My 79 F100 I had a 570 Avenger on it (which made a little more top end) before I went back to the 4100. That's the truck that does 24.3, but there's more then the carb for that to happen.

If you use a Performer intake/4100 you'll likely need an adapter as they are a little narrow. I used a 1" 4 holed spacer on mine... forgot the brand. Came from Summit several years back. I've got a Weiand intake though.

 

I on the other hand prefer the Edelbrock carbs with metering rods. Easy to change, and simple to diagnose power delivery...
My truck came with the spreadbore intake, and 4350 carb. The spreadbore is nothing like a Q Jet spreadbore. Kind of on it's own. Jeep also used this very carb, '76 to '78 or so, but it can be a pain to find rebuild kits for, and just plain annoying as far as tuneable. I had to buy an aluminum square bore spacer and machine it to match the Edelbrock carb to the spreadbore iron intake. There is an adapter available that I found once, but decided to cheap out, since I plan to get an Edelbrock intake anyway. The setup works fine, and is much better than the 4350. No more stumbles when hot.
My mileage improved some too, though I am not sure why... (4V to 4V?)
I use a small 600 cfm right now. In my opinion, fine for a truck 460 up to 4500 rpm, or, just outside of the peak hp zone, and into the fuel economy zone. (If you can call a 460 economic! lol)

 

Like Mil1ion said, run it on the primaries if you can on a 4 bbl. If you want to take -some- of the guess work out of it, throw in a cheap intake vaccuum guage and keep careful watch on it. Your vaccuum pressure is almost directly proprtionate to your mileage. I have this old school JCPenney vaccuum gauge for V8's my grandpa got when he was a VP for them.