Quadrajet rebuild - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mikep · 07-20-2002, 01:18 AM

I went looking for a quadrajet to rebuild for my new motor. Its being built for gas mileage and low rpm towing so I thought I'd go with the quadrajet. I know some of you are groaning but quadrajets just got a bad rap from being hobbled in the 70's with EGR , rediculously lean jetting and other emission controls that made the majority of them run like crap from day one. A well tuned quad is a joy to drive. They came on everything from 429 CJ Fords to 427 Corvettes and big block Camaros. The smaller priamries give good mileage...blah blah blah... You know the spreadbore story ...anyway...

I looked around in the junkyard to find and early model 4MV that I could rebuild without having to rebush the throttle shaft bores. Nothing doing. Every one I looked at was crapped out. All the later ones were emissions calibrated and were definitely not what I was looking for. Then it dawned on me. Stuffed back in the corner in my garage was a 4MV quad that used to reside on my boat before I changed it out for a edelbrock when I rebuilt the engine. I was too lazy to throw it away so there it sat for a few years. I dug it out and as I inspected it it dawned on me that marine carburetors are the way to go for performance rebuilds! The operate in a very clean environment and boats pretty much are on or off without much throttling back and forth not to mention you can go 20 years and only have the engine hour equivalent of 20,000 miles on one. Thats the way this one was. The throttle shaft bores were perfect with absolutely no slop at all. Ive seen rebushed carbs that werent this tight. And to top it off marine carbs are not emission calibrated in any way. This carb is circa 1982 but looks like a 1968 chevrolet carb except its in perfect shape. This particular carburetor had been painted black when mercury installed it on the original targetmaster ( 260 HP mercruiser outdrive ) and took a soaking in stinky carb cleaner, a bath in the untrasonic cleaner at work, a bath in the solvent tank and a trip through the dishwasher ( overkill ! ) to come out looking like new. New gaskets and needle and seat and I'm done. total cost ..$26 for the rebuild kit and this thing is as good as new. I'd suggest to anyone out there who is considering running a quadrajet to pick up a marine model off ebay or at a marina and using it for your base. Even if you paid $60 for it off ebay you'd have a as new Qjet carburetor for under $90 without all the baggage your likely to find on a typical parts shop rebuild. No emissions crap and decent jetting as is.

Littles72 · 07-20-2002, 01:41 AM

I am picking one up off a 69 vette with a small block. Do you think this will work for a mild 350. It has no throttle shaft play and the car it is on runs great. BTW this carb is original with the car.
Thanks David

mikep · 07-20-2002, 01:45 AM

Thats a good one.

Heres a good write up on quads

http://my.inil.com/~dlbrown/ofcrb.htm

07-20-2002, 01:18 AM	#1
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Quadrajet rebuild I went looking for a quadrajet to rebuild for my new motor. Its being built for gas mileage and low rpm towing so I thought I'd go with the quadrajet. I know some of you are groaning but quadrajets just got a bad rap from being hobbled in the 70's with EGR , rediculously lean jetting and other emission controls that made the majority of them run like crap from day one. A well tuned quad is a joy to drive. They came on everything from 429 CJ Fords to 427 Corvettes and big block Camaros. The smaller priamries give good mileage...blah blah blah... You know the spreadbore story ...anyway... I looked around in the junkyard to find and early model 4MV that I could rebuild without having to rebush the throttle shaft bores. Nothing doing. Every one I looked at was crapped out. All the later ones were emissions calibrated and were definitely not what I was looking for. Then it dawned on me. Stuffed back in the corner in my garage was a 4MV quad that used to reside on my boat before I changed it out for a edelbrock when I rebuilt the engine. I was too lazy to throw it away so there it sat for a few years. I dug it out and as I inspected it it dawned on me that marine carburetors are the way to go for performance rebuilds! The operate in a very clean environment and boats pretty much are on or off without much throttling back and forth not to mention you can go 20 years and only have the engine hour equivalent of 20,000 miles on one. Thats the way this one was. The throttle shaft bores were perfect with absolutely no slop at all. Ive seen rebushed carbs that werent this tight. And to top it off marine carbs are not emission calibrated in any way. This carb is circa 1982 but looks like a 1968 chevrolet carb except its in perfect shape. This particular carburetor had been painted black when mercury installed it on the original targetmaster ( 260 HP mercruiser outdrive ) and took a soaking in stinky carb cleaner, a bath in the untrasonic cleaner at work, a bath in the solvent tank and a trip through the dishwasher ( overkill ! ) to come out looking like new. New gaskets and needle and seat and I'm done. total cost ..$26 for the rebuild kit and this thing is as good as new. I'd suggest to anyone out there who is considering running a quadrajet to pick up a marine model off ebay or at a marina and using it for your base. Even if you paid $60 for it off ebay you'd have a as new Qjet carburetor for under $90 without all the baggage your likely to find on a typical parts shop rebuild. No emissions crap and decent jetting as is. Attached Images __________________ No truck :-( Last edited by mikep; 07-20-2002 at 01:35 AM.

07-20-2002, 01:41 AM	#2
Littles72 Registered User Join Date: Jan 2002 Location: Pioneer,CA,USA Posts: 61	69 VETTE QUAD I am picking one up off a 69 vette with a small block. Do you think this will work for a mild 350. It has no throttle shaft play and the car it is on runs great. BTW this carb is original with the car. Thanks David __________________ 1972 short fleet and soon interchangable short stepside beds 2wd with 68 front clip 350/700r4/3.73s 15x8 Truck rallys with 235/275 60s Orange and Black soon to be all Orange

07-20-2002, 01:45 AM	#3
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Thats a good one. Heres a good write up on quads http://my.inil.com/~dlbrown/ofcrb.htm __________________ No truck :-(



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