Beard_75

Evening everyone. I'm looking to purchase a rebuilt quadrajet for my 1975 L82. Just lookin to freshen things up before I do serious engine work and the current carb is in poor shape. I've noticed a few sites say the almost identicle looking carb isn't compatible for my L82. All the emissions equipment was removed by a previous owner and I'm just a bit puzzled on what carb I can purchase without making an uneducated guess...

jim2527

Start with the number off the carb and find what it's from. Do NOT buy one from a truck.

You could always have yours rebuilt. If you have reasonable skills buy the Ruggles book, combine it Lars' papers and do it yourself.

Remember, smart people always say 90% of all carb problems are really ignition problems....and it's true.

Brcmpbl

Do not buy a commercially rebuilt quadrajet. It's not worth your time and money to do that. They are often a mixed bag of parts, and that makes tuning them nearly impossible. Quadrajets were, from the factory, application specific.

If the quadrajet on your car is in decent shape but just running sub-par, absolutely try rebuilding it. It's actually pretty easy - really it is. You just need a kit and a good way to clean the thing up. This is also by far the cheapest option probably.

USA-OSC

Totally agree with first 2 post. If you decide to try a rebuild yourself I would first disassemble carb and do an assessment on the condition of the parts. Now you can order a kit and any misc parts you think need to be replaced.
I also bought a used $30 carb from craigslist to use as a road map. Worked for me and am very happy with the results. Good luck.

jb78L-82

All good advice^. Do not buy a rebuilt...most are junk. I would:

1. Rebuild it yourself if you can
2. Send it to Lars for a rebuild if you can't do #1
3. Buy a NEW Holley 4175 650 CFM vacuum secondary Q-jet replacement carb (made to replace the Quadrajet)...I have had a 4175 on my 78 L-82 since 1985 (rebuilt it for the first time in 2010) and currently being used on the rebuilt L-82 with AFR heads and Roller cammed L-82 355....works great on the rebuilt engine as well with minor jet changes.... Great carb!

Easy Mike

Original Q-Jets were #7045210 L-82 with AT; #7045211 for L-82 and 4 speed.

Redhook98

Rebuilding is surprisingly easy. Take your time and you'll nail it. I always rebuild my carbs on top of a stretched out towel (lint free of course) so that the small parts do not get away from me if dropped. Just a thought.

jnb5101

As posted above, rebuilding your carb is the best option. However, an even better idea is to spend $30 and buy the worst looking POS carb that reasonably matches your carb that you can find on ebay (assuming it is intact) and disassemble it first. That way, you'll gain experience in dis-assembly and possibly have a few spare parts such as down tubes, shafts and springs. And, you'll end up with a carb body that can be used as a test-bed for calibrating power pistons.

lars

If you're not concerned about "numbers-matching," don't use the '75 carb. The '75's don't have the adjustable APT (power piston height), and they utilize a non-needed rear choke pulloff. Rather, find any used (not rebuilt) 1976 - 1980 Chevy passenger car carb. Many of these are actually 800 cfm carbs (the usual is 750), but any of them can be rebuilt and set up to run very well. There are a lot of them for sale on eBay, but quite a few are junk or commercially rebuilt carbs. For more info, you can e-mail me for info on commercial carbs and info on my "carb screening service."

Lars
V8FastCars@msn.com

ksbunting

I sent my quadrajet to Lars years ago for my 68 and it still runs like it just came from the factory. He is a genius and knows these carbs inside out. Cheapest and best route in the long run.
Kurt

7t9l82

There is no bad advice in this thread. Lars is the expert on this subject,I would consider his thoughts Golden.

GUSTO14

Here's one for a '73 Corvette... (near Raleigh)

750 CFM Quadrajet Carburetor 1973 Chevy C3 Corvette
https://raleigh.craigslist.org/pts/5434231009.html

Good luck... GUSTO

lars

The '73 Q-Jet is a 4MV carb. The '75 Vette uses an M4M. The two carb models are not directly interchangeable. He needs a '75 - '80 carb as noted above, and I'd suggest not using the '75 for reasons stated. If using the '73 4MV, the choke would need to be disabled, or the intake would need to be changed.

Is the carb damaged? What makes the carb "in poor shape?" If the carb is original, undamaged, and not a commercially rebuilt carb, it's probably the best candidate you have for a nice setup on your car.

Lars

Primoz

When we are here with the debate on Qjet. I checked the numbers on mine (71 vette with 350 engine) and guess what? It's from a truck!!!! Now I'm looking at Holley 4175 but I do have performer RPM intake on the engine. Does anyone have any experience with this configuration?

7t9l82

A performer RPM is a square bore intake making an adapter necessary for the 4175 and the quadrajet it just makes everything taller. Something like a holley 3310 would be able to handle just about anything you ever do with that engine and would run very nicely.it is not too big a carburetor in spite of what some may say.another option is quick fuel they make a good product.there are some carbs that look to me like they are modeled after a thermoquad but I have no experience with them. They seem to gimmicky for my taste.

Primoz

Thanks for the tip. That quick fuel carb looks nice. Will look into it. This is the first time I heard of quick fuel so thanks.

7t9l82

I have a quick fuel carb on my car,in 4 years it has been flawless and easy to tune.it is every bit the equal of holley and may in fact be better.

hamck

Pardon my stupidly but whats wrong with a truck carb? Are they made different than a car carb?

lars

There's nothing wrong with the pre-'75 4MV (divorced choke) truck carbs - they are the same as the passenger car carbs in most cases and can be set up to run just fine. The 1975+ M4M light duty truck carbs are not good candidates for use on passenger cars due to the "fat-tipped" primary rods and the air bleed systems set up for low-rpm trailer-lugging operations.

Lars

Alex66

Same here for my 71 L48 383, absolutely Perfect!!