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Cars > SNL71’s Garage > Blog > Adjusting a Quadrajet carb


SNL71’s Profile Photo


M –49
Lincoln, Nebraska
United States


SNL71’s Blog Posts 1 – 3 of 3

Adjusting a Quadrajet carb

By SNL71

I have a Rodchester Quadrajet Carb on my 71 short box and when i purchased it the truck engine was set up to run in Colorado and i brought it back to nebraska and it just drinks the fuel and i can figure out the adjustments to bring the idle down and the fuel mixtures. If there is anyone that is out there in these site that can give me some helpful advise it would be very much appreciated.
I have already heard switch to a holley and the quadrajets are junk so if your advice is that please keep them to yourself.


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Read comments on this blog post 1 – 10 of 23

rj_’s Profile Photo
Nov 24, 2008 at 12:07 pm
Scott, looks like you've got some excellent advice to date. Just wanted to tell you I run three Q-jet carbs. Cause I happen to love them. To me they're better then 90% of the Holley's out there.
If you can find someone to trust to do a re-build on your Q-jet, you'll love how it performs.
Good luck. RJ
Girthman’s Profile Photo
Nov 20, 2008 at 5:33 pm
Yep, quads are great. Sounds like a rebuild is in order. Check the throttle bushings for wear. If there is slack it will cause a vacum leak that is hard to detect and give hell trying to tune it. Also while you have it apart check the casting plugs on the bottom of the carb body. You will see them once you have taken the throttle plate off. These will leak and also cause tuning issues. You can seal them up with epoxy. Good luck Gettin' er dun..
blubyu’s Profile Photo
Nov 20, 2008 at 12:34 pm
I would consider checking the metering rods for the size. Try putting the factory size in and adjust from that. I have Holleys, but I am not saying one is better than the other. Good luck.
xoutlaw’s Profile Photo
Nov 18, 2008 at 2:32 pm
Q jet can be a very effective Hi perf piece.
They came on many big blocks well tuned they will do the trick and can actually be pretty easy on gas .... if you stay out of the giant back barrels.. but what fun is that ?
If you want it to go-- send to "JET performance" ask for STAGE III mods -- or find a good local hot rodder.
camaro1093ac’s Profile Photo
Nov 17, 2008 at 3:18 pm
the quad is a great carb. it has metering rods that can be changed like jets . I would do a web search and see what comes up,lots of guys swear by them,good luck.I have to find a local guy to tune my holley double pumper ,it`s a pain trying to find someone.
david286’s Profile Photo
Nov 17, 2008 at 1:20 pm
Quads are awesome...sounds like it needs a rebuild though...Not a big deal really.
sinbad89110’s Profile Photo
Nov 16, 2008 at 5:35 pm
Quadrajets are damn good carbs, you just might have too much carb, or go with smaller jets.
FriedGreenTMater’s Profile Photo
Nov 15, 2008 at 3:07 pm
I have always had better luck with quadrajets than anything else but it sounds like yours may have a problem. The air here in Colorado is thinner so therefore it should be starving for gas down lower in elevation not using more. Get a rebuild kit and a gallon can of carb cleaner/soaker with the basket from Napa or other parts store and rebuild it. They are not really that complicated and are easy to rebuild.
MoparPete’s Profile Photo
Nov 15, 2008 at 10:18 am
It sounds as if you are not much of a carb man. The best bang for your buck is an edelbrock AFB carb they are simple to tune and usually are set right out of the box
tamatt79’s Profile Photo
Nov 15, 2008 at 9:28 am
LOL, the quads are actually very dependable, and flexible to a certain extent. Wish i could help you out, but not an expert on carbs. Have seen quads in a lot of different applications. Holleys arent that much better, just cheaper, and easier to work on.

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