M22 has a 2.20 first gear. Combined with a 2.93 rear and a tall tire.....not a very good combination. Would be pretty doggy off the line. But you have bigger problems right now. That carburetor likely just had a vacuum leak in it, not a issue with the idle tubes/ restrictors. Junk now but on the bright side you didn't destroy an $1800 7040243 real 70 455 4 speed carb
Sorry I was confused, my actual transmission is a M21 not a M22. Vacuum leaks were discarded at the time when dealing with that QJ. I just found the channel restrictors and idle tubes on quadrajetpower.com, I think I need to figure out what size will fit better this carb taking in mind is going to live on my 455 (if the rebuild succeeds off course)
Might as well get the correct one like every poster has suggested rather than trying to fix a 1978 Chevy carb. Its not a 78 Chevy right?
Surely isn't but I'm not sure about spending big numbers on a 70 matching carb because maybe I'll consider a FI upgrade by the end of the year How do you know it's from a 350? I'm not sure if that information came in the serial number
17058213 thats the # you wrote.. I googled it google comes back with == https://quadrajetpower.com/chevrolet-1978-350-quadrajet-17058213/
Makes sense then What makes you think will be too small for a 455? If I'm right this is a 750cfm quadrajet and with the right channel restrictors and idle tubes I think that theoretically should work. Or is there something else involve with quadrajets? By the way tomorrow I'm going to do the inspection on my car trying to figure out the issue, what I'm going to do: -Modify initial advance to 14° and total advance up to 34° -Change HEI module and check voltage at distributor (last time I checked was a solid 14V while running but just to be sure nothing has changed) -Check if maybe an air bleed on the current carb is blocked or something -Check valves adjustment
Your right #s correct is not really worth it. if you look back in this thread Larry70gs in his sig you'll see he is running a 7042240. That carb is a 1972 800 cfm
In theory maybe, in your country. here no we don't get 1970 gasoline. I have no idea what your gas is like.. Boils down to you really cant use a 50 year old book to build a motor or carb in todays world..
Gas here is just expensive aerated junk with ethanol content . But what does gasoline quality has to do with air flowing capacity?
You really need to listen to these guys. I haven't played with cars in 30 years. Yes Ive worked on my 350 chevy boat motor. thats not a Buick. Different set of rules.. Cummins diesel different world Boils down to it the guys on this board are trying to save you Time Money.
Im not going to even try to answer that. I cant. The guy that built my boat motor told me what to run.. He build it to run low grade but It runs great on hi grade so Im lost on that.. I got a Subaru It don't care what of grade of gas corn or corn less it runs the same..
I really appreciate all the help you guys are giving me. Let’s see what I find tomorrow and then get back to the carb thing
You should learn to crawl before you start entering marathons. If you cant get the car to run well with a carburetor, how are you possibly going to figure out a fuel injection upgrade?
I think you misunderstood one of the main suggestions. You don’t have to buy a numbers matching $1500 carb, just buy a $300-400 carb that’s correct for a Buick 455. That will likely be quicker and almost certainly work better than that facked up truck carb you have now. If you can source the parts for it, the same supplier can ship you a carb. Good luck! Patrick
q jet to small? ( from above comment) in all my reading and experience, 4 barrel Qjet only came in 750 and 800 cfm, good article on them.........https://www.chevyhardcore.com/tech-stories/choose-your-quadrajet-number-identification-guide/
The biggest difference is in the idle system. A 455 at idle needs more air than a 350. You can modify a 350 Q-jet to work on a 455.
So today after working on car I have the smooth idle back or at least as smooth as it was before because I've ever have the feeling that the idle could be even smoother but maybe is due to what we have been talking about my carb being too small I set the initial advance at 14° BTDC and after recurving the distributor I've a total of 36° (without vac advance) all in at 2600RPM. At 14° my vacuum is about 18" at 700 RPM but at 18° my vac is about 20", should this be this way or maybe the greater vacuum with more advance is a signal of something else? some of the power is back but I still feel like it doesn't have the "punch" at WOT or part throttle than it should honestly it feels like a V6 caprice that I had two years ago , I think my next move is to check the jetting, maybe a thinner rod would help. About the QJet I'm considering the option of changing it for a 800CFM instead of modifying this to work on a 455, honestly I'm not sure if the mod would be too hard to be done all by myself so better to be on the straightforward path to have my car running properly
Instead of guessing about the air/fuel ratio, maybe get an A/F ratio gauge on it? @ 5,600 ft, the carb is letting in less air so if any direction to go it would more than likely be to lean it out? But if you want to know for sure get the mentioned gauge?
