Helping a young neighbor who's Dad recently passed away, clean out his garage/ shed and came across these two Carter/Quadrajets. I have no idea the CFM rating of them, hope someone can help. I've been told that Quadrajets can be a pain to rebuild and finicky to work with so I'm thinking the neighbor's Dad, who had a bunch of Corvettes, may have pulled these and replaced them with Edelbrock or Holley carbs. Can anyone ID them? Should I just trash 'em? The numbers on one are...8904 1901, 0983 W......and the second carb is 7044217, M1 ....FF. Any help is appreciated.......Thanks, Don.
7044217 is a 1974 GMC motorhome (read Bigggggg truck) with automatic transmission carb. And one that proves that the "last digit even automatic, last digit odd stick) transmission code is not always correct. The other is not either a Carter number or Rochester number (at least that I recognize) and may be a clone. Jon
I believe the first one is an Edelbrock with the 1901, the second was from a 1972 Chevy or gmc truck with a 402 or 454.
sure, they're great carbs. Edelbrock made this years ago, probably in 1989, per the date code Q-JET SERIES CARBURETOR - 4MV - 1966-73 For 1966-73 327-454 Chevy/GMC trucks and cars with a divorced style choke. Compatible with EGR. Main Jet: .069; Metering Rods: Primary-36B, Secondary-DR. 750 cfm with divorced choke #1901
Thanks guys. So Quadrajet isn't really a "brand" per se, but a style of carb originally made by Carter and Edelbrock made a Quadrajet later on?
pretty sure it was designed (and most were built) by Rochester....and it's a trademark name, and the design was licensed to Carter and later Edelbrock, afaik.
Based on the photos, they look to be in great condition which makes them keepers or sellable to the right buyers. Back in the later 60s, I had a slightly O/T General Motors product that came stock with a QJ. I didn't know back then that I was supposed to hate that carb and replace it with a Holley. I just recut the metering rods and tweaked it the way it said to do in one of the hot rod magazine feature articles and proceeded to dominate my class at the local dragstrips for the next 3 years. Boy, was I ever dumb. I know better now.
The Quadrajet was designed by Rochester, the first one being introduced in 1965. As Rochester had insufficient plant capacity to supply Q-Jets for all of the GM brands, Carter was contracted as a supplier to Rochester. Carter was also granted license to produce aftermarket Q-Jets. The Q-Jets Carter produced FOR Rochester carry the 5 digit, 7 digit, or 8 digit Rochester part number (the 5 digit is a special case in 1968 and 1969 where Rochester omitted the leading "70"). Thus if one has a 5 digit number, simply read it as a 7 digit with a leading "70". The Carter aftermarket Q-Jets carry the standard Carter part number (4 digits, followed by the letter "S"). Much later, a number of clones were produced (8 different, if my memory is functioning). The clones do not have a very good reputation for quality machining of the castings. Jon.
Shift Wizard - the magazine advocating "get rid of that Quadrajunk and replace it with a Holley" is the same magazine that 10 years earlier suggested that the hot setup of the dual Carter WCFB's on a Chevy 283 was to replace the vacuum piston springs with those from a Paper Mate ballpoint pen! Jon.
Q-jets are good carbs! But like a lot o stuff some folks don’t understand them or how they work . Then they end up actually tearing them up , bending linkage so that it binds, etc. Most of the time you fine an unmolested carb, it can be rebuilt and made to run properly. Just my experiences. ( but, I’m a Holley man! ) Bones
@carking I have a bad habit of writing more flowery than clearly. I don't recall which magazine because back then I would scan the magazine rack and just buy copies of whatever I thought pertained to me and my Olds F85. At first, I didn't have anyone to mentor and teach me (later I did, though). The article was a How To for all the tuning tricks to make a QJ run like a Swiss watch. The magazines were my only resource at the time. I didn't know what I was doing so I just did what I read. I checked off all the "right stuff" at the dealer when I bought so I had a good starting platform. Along with tweaking the QJ carb I did the advance 'kit', a capacitive discharge, Hooker headers, and some traction goodies. I even changed a ring and pinion with nothing but a magazine article to guide me. It was pure dumb luck that everything worked for me.
I still remember the very first Q-jet carb I fixed. It was on my landlord’s son’s 60s Corvette, in 1971. He found out I was a fledging mechanic and brought it to me. I got a Hy-grade kit , a can of cleaner, took it apart on the kitchen table of my aprartment. Cleaned it, put it back tougher along with the upgrades of the time. Checked and adjusted everything exactly like the instructions said in the kit. He took it back and put it on his Corvette and s told me it ran perfect! Said he didn’t even have to set the idle! But I also didn’t move it! It was the very first time anyone messed with that carb so it was an easy fix. It was an easy fix the next time it was done..... if the next guy knew what he was doing! Bones
Shawn Murphy @ SMI in Huntington Beach Ca. Seems to be able to make them perform correctly. I believe quite a few are on or have been on NHRA Stocks record holders for years.
The only problem I've run across is primary throttle shaft ware. Back in the early production there was talk of cars laying down at the end of a quarter because of the float bowl running dry any experance?
I had one on a 455 Pontiac years ago, and bought a rebuild kit for it from Brad Urban's Carburetor Shop. The kit they initially sent me didn't fit, turned out to be a Canadian-spec Quadrajet based on the pre-emissions design. They were really good about the return and sending the correct kit. With that and a couple of upgrades and tuning tricks from them it ran great.
The Q-Jets are wonderful carbs; but technically, since they came out in 1965, they are all OT. Because of that, will not go into any more here, and my first post, other than the identification requested, was history. If anyone is interested in these, Cliff Ruggles' book is priceless; or I will try to help on pre-1975 models via telephone Jon.
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