Author Topic: '78 carburetor question  (Read 1963 times)

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Offline mikeb78ta

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'78 carburetor question
« on: December 15, 2008, 06:05:56 PM »
Hey Guys,
I have a '78 with a 403 Olds Carb.  It is starting to get a little sluggish and I was wondering if I choose to replace it what the best options for this engine config would be? Any help?
1978 Trans Am 403 WS6, BLack, Camel Deluxe Interior

Offline Rick

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Re: '78 carburetor question
« Reply #1 on: December 15, 2008, 06:54:08 PM »
I'd rebuild it before I replaced it with anything else.  The factory Qjet was a remarkable carb and you don't have the other problems you get with different brands.  Have you looked at Cliff Ruggle's book on how to rebuild your Quadrajet?

Also, keep in mind there's a ton of reasons the car could be getting a little sluggish and the carb is only one of them.  What else have you checked?

Offline mikeb78ta

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Re: '78 carburetor question
« Reply #2 on: December 15, 2008, 07:48:57 PM »
I've had the car tuned up. Plugs, points, wires and I was told that the Accelerator something or other was in need of replacment and that it may be advised to replace.  As usual I wanted any help from other TA owners input before making a bad decision.  I know that the choke isn't working properly. it doesn't open on start up. I guess I'm not sure what I should belooking for. Any Suggestions where else I should Look?
1978 Trans Am 403 WS6, BLack, Camel Deluxe Interior

Offline Grand73Am

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Re: '78 carburetor question
« Reply #3 on: December 15, 2008, 08:13:30 PM »
I agree with sticking with the q-jet. Either get Cliff Ruggles' book, "how to rebuild and modify Rochester Quadrajet carburetors", and get a kit and rebuild it yourself, or buy a rebuilt one for your car from the local NAPA auto parts store. This way everything will hook right back up the way it was too.
Steve F.

Offline Rick

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Re: '78 carburetor question
« Reply #4 on: December 15, 2008, 08:28:40 PM »
I've had the car tuned up. Plugs, points, wires and I was told that the Accelerator something or other was in need of replacment and that it may be advised to replace. 

I'm just guessing, of course, but it sounds like what they were telling you is that the accelerator pump is funky.  That's a part of the carb that gives you a shot of fuel when you goose the throttle.  Fixing that is covered in the book Steve references.

Fixing it is preferable to just replacing the whole thing because the parts place will try to sell you a rebuilt one anyway.  There are some pretty horrible stories around about how badly those "rebuilt" or "remanufactured" parts work.  I haven't heard of many people who were happy with them.  It seems that the guys who get Cliff's book and do it themselves are pretty happy with the results.  He explains things pretty well and it's well illustrated.

Keep in mind that your average tuneup guy will recommend replacement over rebuilding it because it's less hassle for him to just get a rebuilt one and stick it on the car and send you out the door.  It's quicker than actually working on the one you have.

Offline ta78w72

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Re: '78 carburetor question
« Reply #5 on: December 15, 2008, 09:03:32 PM »
A lot of the shops don't know how to rebuild a Qjet anymore.  You're apt to get a vacuum leak in a rebuilt unit anyway.  Best to just buy the book and figure out how to do it yourself.  It's not that hard really.

Offline mikeb78ta

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Re: '78 carburetor question
« Reply #6 on: December 16, 2008, 08:16:11 AM »
Sounds good! Thanks a lot for the insight.  I will look for the book and begin the process.
1978 Trans Am 403 WS6, BLack, Camel Deluxe Interior

Offline ta78w72

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Re: '78 carburetor question
« Reply #7 on: December 16, 2008, 10:02:03 AM »
You can buy new bushings and the drill bit to drill out the throttle shaft to accommodate the new bushings.  They also have the throttle plate screws because you can't reuse them.  And a threader to rethread the shaft.

Here's where to get that stuff:
http://www.tinindianperformance.com/Qjet%20parts%20and%20services.htm