So I just happen to have this extra carb lying around, pretty clean except for the dust, and I just got around to decoding it as I just got the Rochester Carb Book by Doug Roe and am getting ready to rebuild the on on my '72. Turns out the one sitting around (7041540) is a carb from 1971, for a 455 auto. I currently am running the original carb for the car. I was thinking of switching to this other one. My question is, what is the main difference between the two? Is it possible to bolt that one on and run with it? If so what problems or modifications do I need to make to get it to work? Can I steal parts from it to rebuild my current carb? Any advice would be appreciated. Thanks! :TU:
If you are talking a stock 71 455 carb versus a stock 72 350 carb then one is a 800 cfm and the other is a 750 cfm.
Thanks, they are both stock. I am wondering if they are atl all interchangeable. Is there are big difference in linkages between the two? Is there a benefit to using the 800cfm 455 carb? Thanks
Norm Dihle told me they have run equally prepped 750 cfm versus 800 cfm carbs back to back on the same car. The result was the same times at the track.
That is good to know. I am not necessarily looking for more power or better performance (although that would be nice). The original carb was messed with a little bit. The linkage for the throttle and tranny cable is cut and has a big weld on it. I think the PO tried to adjust the linkage for the non original th-700 tranny he dropped in. One site I looked at shows to cut the linkage an re-weld it to get the correct angles for the TV cable, and I think that is what he did. It looks awful, and it just does not look like everything lines up right. So my thought was to drop this 455 carb on which is untouched, and looks fairly unused and start from scratch with the tranny adjustments. If I cannot use it, I will sell it. Thanks!
The 800 CFM carbs for the 455 have 1/8" bigger primary outer venturis. They are jetted richer for this reason. They also have a larger capacity idle system (extra passages) for the big block. There is a fixed idle air bypass to allow the bigger engine to idle with a smaller throttle opening. A 455 carb will work really well on a 350 with a big cam. You may be able to use it for a mild 350. Give it a shot.
Thanks for the info Larry. I have a bone stock engine, except for the electronic ignition. I will give it a shot and see how it works. My main concern is the throttle and tranny linkages. I have issues with my tranny as it is, I will take a pic when I get home of what mine looks like now with the ugly weld, and one of the 455 carb to compare. Thanks again!
Pics of What I got to Deal With Here is the crappy weld on my 350 carb, this is how the TV cable is attached. http://img.photobucket.com/albums/v631/mbgoodwin737/350crappyweld1wtext.jpg One More Crappy Weld: http://img.photobucket.com/albums/v631/mbgoodwin737/350crappyweld2wtext.jpg And My 455 linkage. What should I do, if I bold it on I wil lhave no where to attache my tv cable. http://img.photobucket.com/albums/v631/mbgoodwin737/455linkagewithtext.jpg Thanks guys
How about this: http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=20503&prmenbr=361 Look at the bottom of the page. This will adapt a Q-jet to run a TV cable. Page 154 of the current Jegs catalog.
Larry- That is incredibly interesting. I really appreciate that post. I had no idea that, that kind of stuff was available. I also found this site after doing a little searching. It is the Bowtie Overdrive site dealing with TH-700 transmissions, and they have a whole kit for the quadrajet. It is more expensive, but I was wondering what you thought. Also, they list the Q-Jets as 1901, 1902 etc. How do I know which one I have, or is it completely different. Thanks again for the great advice. http://www.bowtieoverdrives.com/catalog/catalog.php?Action=GETSUBCAT&CATID=WA3A4 How do you think they would compare? The site you posted seems so much easier. Would I have to do anything to the tranny, or just hook up the bracket? I love this site, this is some great stuff!
The 190x number is the numbers of the (now discontinued) Edelbrock Q-Jet copies. The Performer RPM Q-jet was 1910, now sold out. There might be a few of the other part numbers still loitering on parts shelves somewhere. A 9975 is the Edelbrock reman version of the 1910. Still available--for awhile. http://store.summitracing.com/defau...earchinresults=false&N=0&target=egnsearch.asp
ANY parts interchanging done with Q-jets need to be done with the UTMOST caution. Sure, jets 'n' metering rods interchange, (mostly--there was a major re-design in '75) but there are a million different castings which require dozens of different gaskets designs. BE VERY CAREFUL when taking parts from one Q-jet and using them on another!
Thanks for the info. I deceided against interchanging parts. I think I am going to go with the 800cfm carb, and get the bracket/adapter for the TH-700 tranny, and see how that runs. The carb off the 455, like I said before, has not been altered in anyway so it should be better to work with. Thanks
Mike, All I did was post a link to an item in the Jegs catalog. The Bowtie site is good, I've seen it before. I'm sure you'll be able to hook up your TV cable either way.
The main difference between the 750 and the 830 cfm carb is the size of the primaries. It is possible that the 350 engine will not have the necessary signal to operate the venturi, but try it anyway. The difference, only being 80 cfm, across both primary throttle blades, may be overcome by simple feathering the throttle instead of slamming it open. Ray
All Q-jets are warped and have loose throttle shafts Any work done to a Q-jet, should be done after you have un-warped it and installed primary throttle shaft bushings. www.mrqjet.com has the only tool and bushing kit that works every time.
