New carb for 79?

[79transam]

So I just posted a bunch of questions about my 79 T/A with the Olds 403 and Quadrajet 4bbl.  Essentially I am thinking the carb is my main culprit.  So I have heard the Edelbrock Preformer is the route to take.  Not sure on a model or cfm's. I have heard they do not fit well under the hood with the shaker in place.  Anybody know?

Thanks.

[Todd Stahr]

What exactly is it doing? Rebuilding a Qjet isnt difficult, if its beyond your capability or just dont have the time I could do one for you. Chances are it isnt the carb, but that isnt ruling it out either. More information will help to figure out whats going on.

The carter will need an adapter plate to fit the stock intake. That will raise it up half an inch to one inch. Since my 10th Anniversary TA has the 403 in it, and I swapped some things around on it a couple times, I know that the spacer will raise the carb too high to fit the shaker.

I am no fan of the edelbrock carbs, they work ok on stock engines similar to a chevy 350, but they are lacking in a few areas IMHO. One area is mileage, a well tuned Qjet can deliver power, drivability, and economy very near what EFI can do. The Edelbrock is simple and easy to adjust provided you dont need to make changes to how fast the secondary air valve opens, and the Qjet has enough adjustments to overload most people, but getting to know the Qjet isnt that tough.

[79transam]

Hi, thanks for the response.  Fact is I would like to keep the car as original as posible but get frustrated with the hesitation and stalling when started after being asleep for a few days/weeks.  I have rebuilt the carb (thanks for your offer) and am starting to feel it is more a choke problem. Fact, is I do not know what to look at to determine where the choke should be from a cold start or where it should be when running.  I know the butterfly should be open when warm, closed when cold.  How do I set it? When do you adjust it, hot or cold?  The car does seem to run a bit better in colder weather. What I want to be "able" to do is spin my wheels from a light when the car is warm. As it is the when the car is warm and I get on it at a light, it boggs, and leaves but with out the neck breaking power I know is there. The timming is set TDC from what I recall.  Again, I confuse easy on these things.  Do I set timming then adjust the carb?  Or set carb and the timming? 

So in short to answer your question of what is happening /not happening.  I have hesitation when I get on the pedal. When starting after sitting for a while it like to crank quite a bit and requires I keep my foot on the pedal to keep it running until warmed up.  Once warm she starts effortlessly, however there is that hesitation.

Wire and plugs have nearly 3000 miles.  I put them on when I got the car three years ago. It has an Accell coil onwhat appears to be a stock cap. No noticeable cracks or leaks in the cap.  All ends are clean and free from corrosion.

I admit I am not a mechanic, but I can and do like trying things.  I use caution on this matter as it does run and all.  I would regret making adjustments only to have it be WORSE or not start at all!

So, if you can shed some light or tips that would be great.  She is in the garage in sleep mode now.  I may take her for a run this weekend.  But by and large she will be of the road 'till Spring. Winter time is tinker time!

Thank you,
Rick     

[clayton]

i have a 79 with the 6.6 403 and it has been professionally rebuilt by the previous owner some time ago and it hasnt even been on the road since he started getting work done to it....and the plugs and wires and carb(carter 1000 cfm competition = terrible carburetor) had to be 5 years old. anyways i would start it and run it when i wanted to work on it but eventually the car would barely try to run and it was running like it was missing on 4 cylinders or somethin...i was repeatedly told that the carb the previous owner had put on it was rediculous and needed to be thrown out....so i went to my local parts shop and bought an edelbrock 750 electric choke and it went on with no adapter and the car ran extremely well after that....i let it sit for the week, covered and in my barn and i went to start it and it had the same problem, it wouldnt run at all....it was acting like it had a stuck lifter or missing on half the cylinders....so that day i went out and bought new spark plugs for it cuz i noticed the plugs that were in it were old and rusted.....i had replaced the plug wires a week prior to getting the new carb to try and fix the problem...so once the new plugs went in and to this day (three weeks later) the car runs like a damn nascar and starts quick and clean everytime! my point is, youd be suprised what a quality, new, spark plugs and wires will do for your engine.... if everything else is in order for your engine....hope i helped....

[John3407]

I just bought a 79 TA with the 403 last month. Popular car from the looks of the board. It is in need of restoration here and there, but I have/ had almost the exact same problems. Now, I know that my carb does need to be rebuilt, and I cleaned it the best I could,(three spray cans of carb cleaner AND a bottle of cleaner in the tank). I did see some improvement in the response time when I dropped the hammer, but my biggest improvement thus far came when I started replacing vacuum hoses! there was literally no drag when I stomped on the gas pedal from a stop. I can only imagine what she will be like when I get all new plugs and wires AND get the carb rebuilt.  By the way, I will be becoming a member shortly,(I am giving my girlfriend a chance to buy me a membership for the holidays), and I look forward to any advice I can get. I used to own an 85 TA with the 305 TPI, but it was stolen some time ago. I always wanted to replace it, but I never thought I would be able to get a hold of a nice 2nd generation classic. Don't be offended 3rd gen owners,  my realistic dream car is an 89 Indy pace car. I say realistic, because my actual DREAM car is a 69 blue TA. Someone have a hundred grand I can borrow? lol Hope to hear from you all.

[clayton]

yeah i imagine vacuum hoses that are old can get gummed up or creased or even cracks and wont seal well.....having these things taken care of can only help everything.....i too am about in the middle of the process of restoration of my 79 trans am and its my first, although im not shooting for complete origional restoration i am finding things that cause struggles here and there....so just like you any feedback and advice is completely embraced......hope to stay in touch

[John3407]

The old vacuum hoses were coming apart in my hand! Here is another tip for all you 2nd gen owners who don't all ready know: If you end up driving in a freak snow storm and you have problems shifting your automatic transmition when you park, DO NOT slam it into gear! Just put it in neutral, put on your E-brake and maybe some blocks behind the tires. Chances are you got snow in the linkage and your transmission will be just fine after the snow melts. If you slam it into park, you will bend the linkage and then you have work to be done. I live in Cheyenne ,Wyoming , ask me how I know.

Any luck with your 79 TA 79Transam?

[79transam]

Thanks to all for your responses.  I ahd not looked at the vacum line yet.  Not much free time these days, but the winter months will have me in the garage tinkering.  I now have a logical place to start.  I am thinking I may replace the cap/rotor while am out there.

Again, thanks for the feedback.

Rick 

[John3407]

Make sure you check EVERY rubber hose, clamp, seal and grommet.
i have had to replace almost all of them . 30 year old pieces of rubber are not great things to keep under the hood.