carb selection

Posted By: moparsrule

carb selection - 10/17/09 02:46 AM

I have a stock 74 360 with a newly rebuilt thermaquad that I am not having good luck with and want to replace it. I am thinking of going with a Holley replacement carb that I think is 670 cfm. Can anybody give me any suggestions on this carb or any others that may work better.

Posted By: 69rrgrabber

Re: carb selection - 10/17/09 05:09 AM

The Thermoquads are difficult to tune compared to say a Holley or Carter. For a stock 360 mild performance street motor, 600 cfm will give you more throttle response in general and better mileage. Many people like the Edlerbrock 600, but the 750s have problems. The Holleys are good too and if you get one you will want a vacuum secondary version single pumper.

CAC

Posted By: RapidRobert

Re: carb selection - 10/17/09 05:45 AM

I'd send it to Demonsizzler in Stone Mountain Georgia & have him nurse it back to health. He's our resident thermoquad guru & you wouldn't end up with an extra carb.

Posted By: 1_WILD_RT

Re: carb selection - 10/17/09 05:58 AM

Quote:

I'd send it to Demonsizzler in Stone Mountain Georgia & have him nurse it back to health. He's our resident thermoquad guru & you wouldn't end up with an extra carb.

Thermoquads are very capable carbs, mileage & performance when set-up correctly.. Demonsizzler actually knows the carb, most guys that "rebuild" them are changing parts with little idea how the carb actually works & what little tweeks improve the carb vs cost mileage...

Posted By: moparsrule

Re: carb selection - 10/17/09 01:28 PM

I like the Therma Quad carb but I am getting sick of working on this one. I had it rebuilt, cost me $150 and that helped but it is still not right. The Holley replacement carb at the local parts store is a 670cfm that is what they say it takes but I didn't know if that is to much carb for a stock rebuilt 360, it may be 30 over but stock cam.

Posted By: RapidRobert

Re: carb selection - 10/17/09 01:35 PM

670 is not too much for your stock 360. And it's definitely the carb that is the culprit?

Posted By: moparsrule

Re: carb selection - 10/17/09 01:51 PM

Yes I think the culprit is the carb. It has a small leak on the pass. side outside of carb, after I shut the car off it seems to drip fuel in because I can see vapors coming out of the top and if it sits for a few minutes I have to hold the gas pedal to the floor for it to start. And I was driving it the other day around the block and it wants to load up bad and smokes black, if I rev the engine it will straighten up for a little bit. I have tried to adjust the carb with no luck.

Posted By: joedust451

Re: carb selection - 10/17/09 03:06 PM

Quote:

Yes I think the culprit is the carb. It has a small leak on the pass. side outside of carb, after I shut the car off it seems to drip fuel in because I can see vapors coming out of the top and if it sits for a few minutes I have to hold the gas pedal to the floor for it to start. And I was driving it the other day around the block and it wants to load up bad and smokes black, if I rev the engine it will straighten up for a little bit. I have tried to adjust the carb with no luck.

Throttle shafts are worn, its common on these old TQs, also sounds like the main body is worpt, your best bet is a 600 VS if your staying stock.