Check the throttle shafts for excessive wear before forking over any cash. They can be fixed but it's mo money...
It took me a few times rebuilding one to get it right many years ago. After that learning experience i would not hesitate to build them for friends. They were great carbs. It's funny this came up at this time. I was telling my son about my experience of these carbs the other day and that I think I invented new curse words during that time.
When I first built my T, I used one and loved it. It was probably the best carb I have ran, but damn it's ugly. On an open hooded car, it just looks ugly, IMO. But under a hood and a BIG air cleaner, I'd use one in a heart beat.
Haha, if I had the patience to do the work, wiring, etc.. LQ9 or LS would be a serious option, but I like the idea of the ford motor in my ford and the 5.0 is light and makes decent power.. this thing will have as little wiring as possible, trying to keep my first build as simple as possible
http://www.digitalcorvettes.com/forums/showthread.php?t=88376 this is the best article Ive ever seen on them, written by Lars Grimsrud. They are tough to beat when they are right
Ford also thought enough of Quadrajets to put them on a host of performance non-smog small blocks for the Australian market. Jon.
The problem I have found with picking up these carbs second hand is that as the two front mounting bolts go all the way through the carb including the top, previous owner get carried away with those bolts and over tighten them warping everything causing sealing issues. Have a careful look in this area when looking at a potential purchase.
don't know what your talking about , a q jet has less parts than a Holley and Abf , and no powervalves to blow out or have to change with altitude or weather changes . you have a vacume controlled primary jet set , and a secondary vacume controlled jet set , and the mixtures are controlled by the needles not a jet and it adjusts quite well to conditions , hardest part is adjusting the secondary airflap ( you must leave the dampner on it ! ) , once you learn how to do it there easy . a Holley is a gas toilet compard to a Q jet design , and the best thing is the 350 cfm primarys for milage . if you get bad milage its a adjustment issue ussually the float, the idle adjustment ( timing ), as for fine tuning parts there out there just google it . been to the upper 9 second range at 140 mph in the quarter with a Quadrajet . its a great carb once you learn how to tune it . not like a holley slap it on and let it drip . FORD used them on the COBRA jets vs the Holleys , wonder why ??? ( oops just saw jons post )
Get the Quadrajet Book By Doug Roe , not the one by Ruggles ( which is basically a rewrite) , Roe was a engineer at Rochester , I met Doug several times when I raced , very nice guy and helped me tune mine better , we lost a very knowledgeable person when he passed .
Just put some throttle shaft bushing in one a few minutes ago, first one in months. We use to do several a day. Have to agree with the general census, when people take the time to actually figure out how they work and learn all of the adjustments a light seems to go off in there head and all of a sudden that quadrapuke becomes the best carb designed ever...weird.
As a rookie in 1970 I loved Q-Jets, 2GC's, Monojets, hated 4 jets (12 float adjustments) of course the Buick Q-Jets didn't seem to have 1/2 the problems of Chevies. The worst Q-Jets, which Buick didn't have, were the Carters. Funky looking castings, threads crumbling. IMO Of course once you do your first thousand or so nothing should be too hard...well maybe a Motorcraft 4350 ....
Ive run Q-jets since the 70's. Little tricky to get set up but when there right they work great. I picked up a Edelbrock Q-jet at a swap meet for 15 bucks a while back. It looked like it may have been only run a short while if at all. I located a 66 nailhead Q-jet intake and put it on the 401 in my 50 sedan delivery. Wouldn't have anything else on it now.
Q-jets are very vacuum dependent and could be set up to work well on stock engines. Modified engines with funky camshafts, big valves and low restriction exhaust systems can have inconsistent vacuum. They also work better with a manifold designed to be used with one not so well with an adapter. Tuning is best done on a dyno stand so you have actual data.
The quadrajet on my vette has been on there since 1984....has never missed a beat...back in early 70, I put a quadrajet style Holly on there....jerked it off the next day...cut my horsepower and speed in half. My 51 ford with 305 had a 72 quadrajet rebuilt and tuned by me and my mechanic and it got 24.6 and 24.4 mpg running 70-80 with NO overdrive...I have one very very simular to that one on my fleetline that is still in progress...it has a 700R...thinking 30 MPG. If you want to hear either one, they are on Utube....just type in 1968 corvette sunday drive...or 51 ford custom for sale....its blue....and its sold okay.
As stated by many, if set up right the Q-jets can't be beat ! I ran the Holleys for year and seems each year needed a rebuild... Have now 2 Q Jets on a t-ram and haven't touched um in six years. I don't think they look all that great but they work ! Pontiac Slim
One of their advantages is, once they're working the way you want them to, they tend to stay that way. I've had Q-jets that literally sat idle for years on a shelf and, once I put them back on a car, fired up and ran like they did when they were last used. Any time I ever tried that with a Holley, they had a severe incontinence problem.
The tranny is a ford AOD, car will be a street machine.. rug er every now and then but highly unlikely I will be doing much for drags etc.. I know AOD needs a lokar kickdown kit to work with carbs, not sure if/how that applies to the quadrajet vs say an edelbrock
apartently you never raced with one , as for the vacum dependency , never a problem with a 320* duration cam , as for manifold never had a problem with a square bore style open plenum ( we used torquer manifolds with a 1" adaptor) and large open headers ( supercomps ) pressure depression works on both holleys and quadrajets , no depression no air flow , and with a q - jet the motor only gets what it needs .. and with low depression you get a need for volume as for actual data time slips are my actual data . when I see a waterbrake dyno go down track then I will believe in dyno figures ....
I have a pretty mild comp cam, along with the set up I mentioned earlier.. I wanted decent power without a huge gas bill every time I fill.. hence the milder cam and considering the quadrajet.. seems if I can get it tuned properly that might work for me Side note: gas here currently is about $4.75 Canadian per gallon ugh