heat choke quest - Pontiac GTO Forum
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post #1 of 8 (permalink) Old 04-12-2006, 05:43 PM Thread Starter
 
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heat choke quest

I put the factory heat choke on my 71 400 with the quadrajet the first one I got had a bend in the rod about 1/2 from end another I have (that I put on now is a straight rod, which is correct, also would it be place in the slot toward the fron of the engine or the back slot and also when insterted would the clip side of the rod (where it attaches to carb) be facing out or in toward the carb, as I sit now I went with the straight rod in the slot toward the front with the clip side facing out... it closed the flap all the way when cold this way and I idled a while and it opened but only about a 1/2 inch, so Ill have to see of it opens all the way when at operating temps
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post #2 of 8 (permalink) Old 04-12-2006, 08:12 PM
 
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Well.... seeing how you are in Wisconsin the Autochoke may be a good solution for you. However, if was stuck with the "Quadra-Junk" Spread Bore I would get rid of the electric choke and go manual. Better yet.... Get rid of the Quad and get your self a nice Holley 600 double pumper square bore carb with a jet kit and fine tune that thing to run..... The performance difference is far superior. A very small price to pay, and the 400's really respond to those.

Just my 2 cents.

As for your question on the rod placement. It should drop naturally in the correct spot. If it is in the wrong location that means the coil spring is in backwards and when the car warms-up the choke will operate in reverse and flood the engine.

Good luck!
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post #3 of 8 (permalink) Old 04-12-2006, 08:41 PM
 
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Take a hair dryer to the coil cover and adjust the rod accordingly. The chokes frequently went too far closed I once had to prop the choke open with a comb when it got too cold to keep the engine from flooding. The QJ would rather be a little lean in choke than fat.
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post #4 of 8 (permalink) Old 04-12-2006, 10:17 PM Thread Starter
 
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quadrajet vs holley

thanks for the info and input the rod I replaced the first one with is correct fully shut cold and wide open hot so Im set. As for the "quadrjunk" comment a properly built and adjusted quadrajet is as good as any holley no matter what anyone says. The heat choke id definitely out of date but I am dealing with a restored stock gto #s matching 400 m21 4 speed with the stock quadrajet carb and stock everything and I wouldnt even think of going with any other set-up then the stock carb, stock heavy cast intake and the exhaust manifolds. The only mods to the drivetrain is aero chamber mufflers which I absolutely love. But thank you for the input and if I ever do go with another carb itll be a stage II replacement carb....nothing against holley the street avenger etc are great if you dont care about stock..
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post #5 of 8 (permalink) Old 04-12-2006, 10:32 PM
 
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Quote:
Originally Posted by my1971gto4spd
thanks for the info and input the rod I replaced the first one with is correct fully shut cold and wide open hot so Im set. As for the "quadrjunk" comment a properly built and adjusted quadrajet is as good as any holley no matter what anyone says. The heat choke id definitely out of date but I am dealing with a restored stock gto #s matching 400 m21 4 speed with the stock quadrajet carb and stock everything and I wouldnt even think of going with any other set-up then the stock carb, stock heavy cast intake and the exhaust manifolds. The only mods to the drivetrain is aero chamber mufflers which I absolutely love. But thank you for the input and if I ever do go with another carb itll be a stage II replacement carb....nothing against holley the street avenger etc are great if you dont care about stock..
Good deal.... Nice car if it is matching #'s. If that is the case then of course you should stay with the Quadra-Jet. I have just been through my share of carb's, not to mention I have rebuilt quite a few too. My experience is a Qudra-Jet can be a good carb for mild performance. But if you don't care about gas mileage and want pure performance with a carb set-up there are better unit's out there that are much easier and more responsive to tuning. I only mentioned Holley because they are affordable. Good luck with your car! Post some picks
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post #6 of 8 (permalink) Old 04-13-2006, 12:42 AM
 
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As with evey product there are good ones and there are bad ones. QJ's got a bad rep early on because they were tricky to get eh mixture right. They have tapered primary and secondary metering rods, which have to be carefully blanced out with the jets they go in. There are different secondary hangers, which give you faster or slower enrichment and there are several unique features like the secondary air valve acting to control the amount of vacuum seen at the secondary discharge tubes. The QJ represented a cubic improvement over the AFB that it replaced. The primary reason for all the little variables was the problem known as emission requirements. The Holley, in spite of its legendary "oops it backfired, so much for the power valve" was easier to make run richer and a car that is running 5% rich runs faster than one that's 5% lean. The QJ had a small float bowl to keep the amount of fuel that evaporated during the hot soak test down. The Holley, with two float bowls could not pass. The QJ has one major problem and that is the leaking primary well seals where the drilled holes had lead plugs pressed into them to seal them. Probably 50% of 'em leaked especislly under vacuum at idle, causing a lot of cars to fail smog... They finally re-designed the throttle body so the plugs were in their own little sealed chamber and the problem got a lot better. Holley continued to make the same basic units for many years, with some much improved units like the annular venturi carbs. And then Barry Grant came along and Holley had to do some quick catching up. Barry Grant's stuff is very good. The Holley Street Avenger line works pretty well, but none of it even comes close to a laptop programmable fuel injection system. Oh, about going faster with the Holley. My partner and I set NHRA and IHRA records in both stock and super stock in both an automatic 1973 and a 4 speed 1974 SD Trans Ams. Both classes, at that time, required both a stock appearing carb and the iron intake manifold! Low 11's were not bad for a QJ. I can post JPGs of the records if anyone has their doubts. Or just go to
http://www.pontiacheaven.org/pontiac%20history.htm
and page down to 1973. You just might figure out something about "kerno"
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post #7 of 8 (permalink) Old 04-13-2006, 07:28 AM Thread Starter
 
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some car pics





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post #8 of 8 (permalink) Old 04-13-2006, 07:34 AM Thread Starter
 
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wow

yeah kerno, I learned something about you then....between you and lars I feel good about the answers I get to questions
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