CO has been inundated lately with questions about carbs fitting their cars. I still say, if you are having carb problems, send your Q-jet to one of the rebuilders that specializes in Q-jets. The drivability and reliability is never the same with an aftermarket carburetor as with the original carb. Just because the aftermarket carbs are talked up in some threads doesn't mean they are best for all around performance and drivability.

 

For some reason, car people don't seem to understand that magazine and online videos touting aftermarket carbs, brake kits, EFI, etc, are infomercials pushing the sponsor's products. Rochester doesn't sell new carbs and has no advertising budget. You'll never see an article that installs a new Qjet as an upgrade because there's no sponsor profit in it. The reality is that the Qjet is arguably the most advanced 4bbl carb ever designed and probably has a couple of orders of magnitude more engineering and test time and investment than any aftermarket carb. The complexity of the Qjet that allows it to have such precise metering control is also why most people crap on it - they lack the skills or patience to work on them. Holley carbs will always make more max HP - they are optimized for wide open throttle performance, period. If you only drive on a race track, get one. If you drive on the street under widely-varying real-world conditions, keep the Qjet and learn how to work on it.

 

^^x2^^ Love it.

 

I was talking with a guy who wanted to update his q-jet to a "more modern" carb like an edelbrock or holley. He was shocked when I told him that the q-jet design was newer than both...

 

I agree with Old(s) Fart. That carburetor is 55 years old and there is a lot of literature available from mild to wild. When I hung out at Cecil County Dragway in the early 2000’s. The bracket racers timed their launches off the “Quadra-bog as they called it.

 

Is there a good reference book/manual - besides the CSM - available to help guide you through properly adjusting or rebuilding a late 60’s/early 70’s Qjet ?

 

Here is the best book there is. It is written by Cliff Ruggles who is the guru of Q-Jets.


Over the years I have rebuilt several Q-Jets successfully. Last year when I bought my 75 Hurst Olds, it surged at idle. I rebuilt the Q-Jet and still could not get it right. I had a guy who was referred to me by one of our NTOC members rebuild it. The guy really knows Oldsmobiles and Q-Jets. Come to find out the 75 Olds is a one-year design that has some quirks in it. He nailed it on the carb and the carb is perfect. I had converted it to electric choke to begin with which I recommend.

 

SA113 written by Cliff Ruggles. Rochester Carburetors by Karen and Doug Roe, and the Haynes Rochester Manual. Those are will tell you everything. SA 204 Engine Math is a great book to have also.

 

Awesome Joe!

 

Everyday Performance LLC has a new book out.
I havent picked up a copy yet, but there are positive comments.

 

agreed. I tried an Edelbrock and was very disappointed. Went back to the quadrajet and aside from it running a bit lean, I am very happy with the driveability and power of the QJ.

 

I have had a Holley 750 vacuum secondary, a Holley 750,850, and 950 HP on my car over the years, none ran as quick or nearly as well as the Q-Jet. I’m convinced the bad reputation Q-Jets get is from poor rebuilding practices. Let’s face it, the newest Q-Jet is 30 plus years old. Your not going to fix decades of wear with a 30 dollar rebuild kit and a can of carb cleaner from Autozone.

 

Chances are the throttle shaft bushings are worn out,,there is almost certainly decades of crud packed under the air bleeds (nobody removes them during a overhaul!) combined with previous repairs, and mismatched parts, it’s no wonder a worn out carb is almost preferable to a “rebuilt” one.

I don’t think Cliff is rebuilding carbs anymore, but last I checked he still sold parts. For a long time the cheap rebuild kits contained parts not compatible with the ethanol crap in todays gas, cliffs parts are compatible with the fuel today.

 

I'm coming from a world of Thermoquads, but can agree the Qjet is a very good street carb. My '86 Dodge came with a Qjet from the factory so I've had a bit of time with them.

Edelbrocks are junk, and currently I'm on my second engine with a Holley designed carb on top.

If I had the original carb and could've figured out how to switch it to electric choke for drivability purpose (read:my wife wouldn't struggle) I would've had a Qjet tuned to my build since I'm going to be mostly street/cruising anyway. At one time I talked to Ken from Everyday, but then the engine shop said they'd rebuild and tune to the engine and that fell through last minute.

 

I think it's so easy to have a bad experience that a lot of people think buying new is better.

I had a well known Quadrajet builder do a 455 carb for me and it was terrible. It seemed like the fast idle would get stuck on every time I floored it. After slowing down the car would buck like hell until I tapped the accelerator. Once warm it never idled under 1300 RPM's. I sent it back and he returned it no better and even charged me return shipping. Rather than fight it I vowed to never use him again and I'll tell anyone that asks who he is.

Eventually John Herald Jr. did a q-jet for me and it runs awesome.

At the end of the day it cost me well over $1k to get something that worked. Finding a good core now is next to impossible. I sent two 7040251's to the first guy and he said neither were any good. I sent two 7042251's to John and he couldn't make a good one out of the two and ended up building me one from some of his parts and some of mine.

John was excellent. I can't say enough good things about him.


FWIW Cliff Ruggles gave me excellent advice and saved my *** once as well....but he doesn't rebuild carbs himself anymore......

 

SA130P about Carters and Edelbrocks will help you understand them better. They’re a great street carburetor.

 

FWIW, the electric choke conversion kit for divorced choke Pontiac q'jets, appears to be applicable to the '66 thru '69 Olds divorced choke q'jets. I have not talked with Ken at Everyday Performance about it but reading thru his installation instruction sheet for the Pontiac kit it appears so.

 

There's a guy in FL that seems to be the hot sauce for Q jet rebuilds

 

If Sparky's Carb Service is still in business in Milwaukee, they do a good job.

 

YES, YES, YES. I own 3 old cars now. A '71 Honda 600 Coupe, 2 Cyl. 4 speed. A '72 Spitfire 1500, 4 Cyl. 4 speed. The '71 Cutlass Convertible w/ 350. All of them are as original as possible. Tires are upgraded on all of them. The Cutlass is largely as it left the factory, except for HEI that was installed over 3 years ago. I put a mercury switch on the trunk & hood lights, as well as installing a radiator recovery bottle. I belong to forums for all these cars. It seems everyone wants to improve their old car. I'm not so sure about the Olds, yet, as I'm new to this. The worst offenders own Spitfires. Constant upgrades are getting talked about. Then the posts are, "Why doesn't this or that work"? I buy old cars for the sake of owning & driving a piece of the past. Joe states this better than I've heard it before. I don't mean to offend anyone who specifically wants to modify or race the cars. This was done to them back when. Just my opinion. Actually, I have a fairly rare car. A Cutlass Supreme that doesn't have the hood, wing, or added 442 emblems. Just for laughs, this is a very factory original 46,000 mile Honda 596cc 4 speed. Car is the first ones Honda imported, prior to the '73 Civic. 10' long, & it has 145 R 10 wheels. The Cutlass is a lot more fun. Al