2 or 4 barrel

[Ronw435]

Was wondering what everyone thinks about going to a Quadrajet and intake over a 2 jet Rochester for fuel mileage. I am going to have to buy a new carb which is going to be around 220.00. I tried to rebuild the 2 jet but the vacuum piston for the power valve is so bad I doubt that it ever pulls off the valve. I get about 8 miles per gallon and the exhaust will puke out black carbon onto the concrete. The plugs are also black. I has a manual choke and I have checked that numerous times to find it completely open. I have set the float to where there is no way of getting overflow. I have inspected the carb while running and find no evidence of overflow. It doesn't run too bad but it seems like I always have to be resetting the idle mixture. The motor will start and run first thing in the morning without ever using the choke. The truck is a 65 with a 283 and 3.07 rear end gears. The engine is basically stock except for a RV cam. It came with power pack heads. My question is would it be worth the trouble changing to the Qjet.

Thanks for any input
Ron

[PGSigns]

If you have a good one a Qjet is hard to beat.
Jimmy

[Ronw435]

Thats the problem, how to know you have a good one to rebuild when buying them used.

[morethanstock66]

Just my .02, but you will most likely get similar MPGs. The secondaries on the 4 barrel will not open until the primaries are fully open. The 4 barrel will have more giddy-up when you need it, though. The engine is basically an air pump, you get a lot more flexibility with a 4 barrel. Keep in mind that if you have a 2 barrel intake, you have to swap to a 4 barrel one to get the 4 barrel.

[Ronw435]

Morethanstock,

Do you know anyone in our area that is good at rebuilding a used Qjet?

[markeb01]

For what it's worth my mileage always improved when I got rid of a 2 barrel and swapped to a 4 barrel. It was easier to rebuilt and set up a 4 barrel, and easier to make adjustments as needed. Although many swear by them, I'm more of an Edelbrock/AFB guy than a Quadrajet fan. Those are just a pain to me. Edelbrock carbs are easy to change jets, etc.

[morethanstock66]

Originally Posted by markeb01

For what it's worth my mileage always improved when I got rid of a 2 barrel and swapped to a 4 barrel. It was easier to rebuilt and set up a 4 barrel, and easier to make adjustments as needed. Although many swear by them, I'm more of an Edelbrock/AFB guy than a Quadrajet fan. Those are just a pain to me. Edelbrock carbs are easy to change jets, etc.

x2, but I know people who are almost religious with their Qjets

[morethanstock66]

Originally Posted by Ronw435

Morethanstock,

Do you know anyone in our area that is good at rebuilding a used Qjet?

Honestly, no. The carbs that I have rebuilt, I did myself. Which mostly consisted of Edelbrocks and a couple Holleys. I would make a few phone calls, and you might be able to find one, typically older rod shops and mechanics. Sorry..

[Figuarus]

I've got a Q-Jet, and mileage wise, it's not a HUGE increase, but any little bit helps in these trucks.

remember to jet it for altitude in case you live in an elevated area.

just to give you an idea, I have a 283 with a TH400 behind it and am running 30" tires with a 4.11 rear end. I can get up to about 14 on the highway, and about 11 in the city if i'm gentle with it and cruise.

[TJ's Chevy]

I believe Edelbrock makes quadra jet carbs still. Not sure. Even with a regular 4 barrel you'll get better mileage and power over the 2 barrel.

[AcampoDave]

On my 283, I run a 500 cfm manual choke Edelbrock jetted 2 stages leaner in the cruise mode. I paired it with a performer e.p.s intake and I think it's great. Lots of members here put down on the Edelbrock carb, but I think that they provide an exceptional value with excellent tunability. Staying with the small one helps with my throttle response and a street driven 283 wont suck enough air for anything bigger. (I just had mine at over 9000ft above sea level last weekend and it still did okay. Just a few momentary light throttle bogs that went away as I accelerated.)

[WorkinLonghorn]

My question is would it be worth the trouble changing to the Qjet.

Thanks for any input
Ron

I sure would. Just go to the nearest self-serve junkyard and pull the manifold and carb and buy a rebuild kit. The kit will include instructions and there are write-ups here on this site to help if needed. It really is easy.
I rebuilt my quadrajet when I bought this truck in '96 and it is still working fine and I get 11-12 MPG mixed driving, 60 city/40 freeway and this truck weighs 5500 lbs. with tools etc. That is with 3.73 gears and an HEI type ignition and 60 MPH max.(usually!).