Quadrajet or ???

[Thumpin455]

I completely forgot that Ford put Qjets on Clevelands. I know about the 429 getting them, that is well known. It just so happens that the Qjet is my favorite carb, I run them on my Pontiac engines and modify them to run E85. So far there are only two of us modifying them for E85, but I have showed others how to do it, and it isnt hard. I rebuild them often and they are easy to work with once you know how they work. A bit more complicated than a Holley, but that means they are more adjustable at part throttle.

The idle down tubes get clogged after the carb sits a while with gas in it. They varnish up and they only have a .038"-.044" hole. Clean those down tubes, install throttle shaft bushings, set the float right, play with the idle screw passages and you are half way to having it set up to run again with todays gas. There are other things that can get plugged, but its usually a simple matter of taking it all apart and running a small wire through the passages.

If you want to do it yourself, spend the $30 and get Cliff Ruggles book on rebuilding and modifying them. http://www.cliffshighperformance.com/buy_book_2.html Otherwise you can send it to me, I will go through it, make it run on one of my Pontiacs with similar vacuum specs and send it back. Its fun for me to work them over, so all I need is the kit to rebuild it and some return postage.

That rash of people having issues with ethanol in the fuel was more a problem with the sludge being cleaned out of the tank, lines, and pump. Ethanol will wipe the varnish and crud right out of your fuel system leaving it squeaky clean. So you need to change the filter and flush the lines so it doesnt get stuck in the carb.

I've been running ethanol in my old cars for a long time now, 10% since the late 80s, and E85 in a couple of them since 2007, all with stock fuel systems. The only mods needed for carbed cars to run E85 is opening the carb passages a bit. If you have to run race gas due to compression, such as in the 71 BOSS 351 or the 429, its easy to modify the carb to run E85 and not have a problem with ping or detonation ever again. It doesnt hurt Qjets a bit, Ive had one soaking in a gallon of E85 since 2006, and properly set up they run great on the stuff. The other guy building Qjets for E85 gets between 16 and 19mpg with a 455 in a 79 Trans Am, its hard for some people to get that on gas.

 

[cazsper]

I have good luck with both a Holly and a Deamon. I have heard a lot of people have had issues with the Deamon but I love mine. There is also the Edelbrock (old Carter AFB) but everyone I have spoken with said they tend to stumble a bit at part throttle. But I have never used one.

 

[TommyK]

I completely forgot that Ford put Qjets on Clevelands. I know about the 429 getting them, that is well known. It just so happens that the Qjet is my favorite carb, I run them on my Pontiac engines and modify them to run E85. So far there are only two of us modifying them for E85, but I have showed others how to do it, and it isnt hard. I rebuild them often and they are easy to work with once you know how they work. A bit more complicated than a Holley, but that means they are more adjustable at part throttle.

The idle down tubes get clogged after the carb sits a while with gas in it. They varnish up and they only have a .038"-.044" hole. Clean those down tubes, install throttle shaft bushings, set the float right, play with the idle screw passages and you are half way to having it set up to run again with todays gas. There are other things that can get plugged, but its usually a simple matter of taking it all apart and running a small wire through the passages.

If you want to do it yourself, spend the $30 and get Cliff Ruggles book on rebuilding and modifying them. http://www.cliffshighperformance.com/buy_book_2.html Otherwise you can send it to me, I will go through it, make it run on one of my Pontiacs with similar vacuum specs and send it back. Its fun for me to work them over, so all I need is the kit to rebuild it and some return postage.

That rash of people having issues with ethanol in the fuel was more a problem with the sludge being cleaned out of the tank, lines, and pump. Ethanol will wipe the varnish and crud right out of your fuel system leaving it squeaky clean. So you need to change the filter and flush the lines so it doesnt get stuck in the carb.

I've been running ethanol in my old cars for a long time now, 10% since the late 80s, and E85 in a couple of them since 2007, all with stock fuel systems. The only mods needed for carbed cars to run E85 is opening the carb passages a bit. If you have to run race gas due to compression, such as in the 71 BOSS 351 or the 429, its easy to modify the carb to run E85 and not have a problem with ping or detonation ever again. It doesnt hurt Qjets a bit, Ive had one soaking in a gallon of E85 since 2006, and properly set up they run great on the stuff. The other guy building Qjets for E85 gets between 16 and 19mpg with a 455 in a 79 Trans Am, its hard for some people to get that on gas.

Ford never put quadrajets on clevelands. I do not believe the carb being discussed is a quadrajet but rather a Motorcraft 4300 which is a spreadbore carb but is not interchangeable with a quadrajet.

 

[hyena429]

Ford never put quadrajets on clevelands. I do not believe the carb being discussed is a quadrajet but rather a Motorcraft 4300 which is a spreadbore carb but is not interchangeable with a quadrajet.

Ford installed GM Rochester Quadrajet on the 429 V-8 in '70-'71. General Motors introduced the Quadrajet in 1965, . The Quadrajet was the auto industry's first spread-bore design and, properly tuned, it is an excellent carburetor. "Spread Bore" means huge secondary bores with small primaries for improved fuel economy. The Quadrajet has an air valve secondary system just like the 4300 and 4300D. It is also the same 715cfm size as a 4300D.

Although the majority of Quadrajets were manufactured for GM vehicles, a handful went to Ford, and they were unique to the 429 and 429 Cobra Jet.

rochester..autolite...and motorcraft all made a quadjet for the most part...I consider the 4300d spreadbore a quadjet...cause looks a lot like a Rochester Quadrajet from GM, and because Ford borrowed a lot of Quadrajet engineering ideas during development of the 4300 and 4300d...But i dont think he was thinking they were interchangeable...hehe...Just saying he forgot about the ford q jets

 

[Jim and Jutta]

Cause they are worth more than your whole motor in value sometimes...lol...Autolite 4300D series which has a spreadbore design, small primaries and oversized secondaries fetches upwards to $2500-$4000.00

I finally took my 4300D off of my car because I could never get it to run "just" right even after a $400.00 rebuild last year by a guy who's been working on them for over 30 years. It was just way to cold natured and if I wasn't careful I'd flood it. I was thinking I tossed that $400.00 down the drain but maybe not. I'm running a Edlebrock Thunder Series on the car at the present time and happy with it so I stored the Autolite in the garage. Here's some pics, is this one of the 4300's that's in demand?

Jim

 

[hyena429]

I finally took my 4300D off of my car because I could never get it to run "just" right even after a $400.00 rebuild last year by a guy who's been working on them for over 30 years. It was just way to cold natured and if I wasn't careful I'd flood it. I was thinking I tossed that $400.00 down the drain but maybe not. I'm running a Edlebrock Thunder Series on the car at the present time and happy with it so I stored the Autolite in the garage. Here's some pics, is this one of the 4300's that's in demand?

Jim

Well Jim..Its usualy the 4300d spread bore version bringing the most..Just cause it was the same carb they put on the boss...But that being said...I believe all 4 barrel high performance ford factory carbs "specialy with tag still on them" Are going to bring huge bank in the future...Right now..Alot of restore shops are picking them up by the tons..and taking them off the market and tring to keep it on the down low ..they are getting valueble. "kinda like the rare pontiac quads and such"....So many got tossed in the garbage..Even replacement carbs are becoming a bit high...Pony carbs sold there good "but mutt carbs" missing tags and such...for allmost 1000 bucks...lol...Cause for that guy who wants a fully stock mustang ..They need that carb...And alot will pay threw the nose for it on the right build.

Btw...Ill check on your numbers on that carb tag later tonight and see what i can come up on it.