hi guys i hope you had a happy new year

i have a 600 holley double pumper carb and it started to give me problems so my buddy gave me a rochester carb. He had it sitting in his garage for a while. He bought it at a garage sale but didnt know what it was from. So is it wise to replace my used holley for a used rochester??? The rochester is a quadrajet that was made in the U.S by GM. Im guessing this is the
part # 17085226 right below it has another # 1615 HI Y ( dont know if its a 600, 650, or what???)

any help will be greatly appreciated
i really dont want to replace a fairly good carb and make a big mistake.
thanx

The carb will flow either 750 or 800 CFM, all Q-jets came in these two CFM ratings. Apparently the Q-jet can use some 'air-on-demand' method of flowing air for the engine, so even though they are high CFM ratings, you won't 'overcarb' your engine. Someone correct me if I'm wrong.

I'm not sure how to decode those numbers. Quadrajets, if built and tuned right, from what I hear, can be good or even better than Holley's. Don't know if it beats a double-pumper though..

I've only rebuilt one carb in my life (and haven't even put it on my engine yet), but even with my limited knowledge, I wouldn't slap an unknown carb on something without going through it to make sure things are okay, internally.

Try looking up that number on the web site called "quadrajet.com" and see what it was used on. The quadrajets were made by Rochester (GM) and also under license by Carter. I suppose that the parts should interchange OK. Check the throttle shaft for wear before wasting any money on a rebuild kit.

If your intake isn't for a spread bore, it's an easy decision. Don't bother. smile.gif Just get a kit and a good book and get that Holley working. ;) If you have an intake like the Edelbrock Performer that accepts both types of carbs, it'll fit, and wouldn't be a big deal to slap it on to try it out.

thanx allot on the heads up. ill check those #'s

that web site "quadrajet.com" jwagner put up got some good information. the carb is from an 85 to 87 chevy /gmc truck now the question is will fit a 71 malibu engine???

if i am correct that carb wont work because it is computer controlled.

meaning the carb is just not for my car. thanx i was having second thoughts about the winchester because i dont even know if its good or not..
thanx again

p.s. my holley has been rebuilt before. will another rebuilt affect its performance???\

jacob. :confused:

Define "rebuilt". If the throttle plate (shafts & butterflies) hasn't been apart/re-sleeved, and just a cleaning with new gaskets, squirts, jets, etc. you can "rebuild" a zillion times. When you have to get into the throttle plate area there's only so much you can do.

The upper 2/3's of a Holley are simply precision castings and holes flowing air or fuel. As long as the mating surfaces or threads aren't boogered usually a thorough cleaning, re-gasketing, and adjustment will bring them back to new.
The trouble comes in when you've put 27 return springs on the linkage, with 450 lbs. of force on the primary throttle shaft. The shaft makes the hole in the aluminum throttle plate an oblong. Once this has happened forget about tuning one. If it's not too bad it can be reamed and sleeved, but only by a competent carb shop.

just a good cleaning new gaskets, and jets. the basic keeping up with the carb. i dont think anyones messed with the throttle plate.

needs allot of adjusting though. tongue.gif

thanks for the link.

i have one of them computer carbs i got and i found i couldnt run it on my velle. so today i just got another q-jet, non computer and now i have a rebuild kit too ( that i bought for the other one) and gunna use it on the new one i got.

im in the middle of reading the quadrajet site now so thanks again, good info. and in the new CHP they have a think on how to rebuild holleys and q-jets.

one question.. are all q-jet rebuild kits the sam?, a friend told me they were. i just want to make sure they are before i break the seal in the box, and cant exchange it.


aaron

The kits aren't all the same. You may not have all the correct gaskets, depending on the kit.

Originally posted by Jrocker84:
just a good cleaning new gaskets, and jets. the basic keeping up with the carb. i dont think anyones messed with the throttle plate.

needs allot of adjusting though. tongue.gif Give these tech articles a read and see if they don't help you with your Holley. Once setup properly you shouldn't need to be adjusting your carb all the time...

http://www.camaros.net/techref/series_2.html

Originally posted by ZZ69chevelle:
The kits aren't all the same. You may not have all the correct gaskets, depending on the kit. ok..

the car i recently got is a 77 non computer carb, and the old one i have is an 86 computer cab, both Q-jets.

so i should just take the kit back and get one for that year then? i may do it this weekend yet.

aaron