I just picked this up... Did this just start after you got the heads redone? Could very well be that the valves are sunk in the heads to far and not closing all the way causing a lot of issues.
After the valve job the car was fine not sure about vacuum at idle but idle was smooth, power has never been great but now its a lot worse
You have to try and avoid using "feelings" in the diagnostic process. If you think the engine is running hot, install a set of gauges under the dash and find out exactly what's going on. If you want to figure out exactly what's going on with your carburetor, install a wideband. And make ONE change at a time. Make the change and test. Your driving a 455 with a stick. Even a mild 455 should be buckling the asphalt behind the rear wheels when you get on it and pressing you back in the seat. . If you get that engine running good, you'll be in that pedal every stop light. And please.....Test, don't guess!!
If you have the original Q jet or a good front feed Q jet send it to either Ken or Mark on the board here to have THEM build it for you.
I did, even did a leakdown for 3 hours before having the heads back in the car and both heads where sealing fine Unfortunately that's not possible since I don't live in the US . usually nobody wants to deal with a QJ where I live, when somebody is having problems with one they just simply throw it away and installs a Holley so I'm on my own with the QJ rebuild or buy a rebuilt ready. I'm going to spend some time with the car tomorrow, I think I have a temp gauge in some place in the basement, the one on the car is working but honestly I don't thrust it at all but usually stays below the middle mark of the dash temp gauge Also I'm going to change the HEI module just to discard a module issue
Hey josehf34 not sure where in the world you live but here's a rebuilt 73 Qjet for sale in Canada. https://www.kijiji.ca/v-engines-and...73/1384691017?enableSearchNavigationFlag=true
Ahhhh ok, well knowing that, use a Holley double pumper, AT LEAST 750, an 850 would be better. The reason for the Holley over the Q-Jet is the Q-Jet's were VERY specific for the engine it was to be used on. The chances of you getting a mystery Q-Jet spot on for your application are very slim. The Holley carb is pretty generic and will cover a lot of "bad spots" so to speak. Im going to go out on a limb here, but I think that's were Chevy guys say a 600 cfm carb is enough for a 350, I believe its the design of the heads that dictate how well a certain carb will operate on a certain engine, or to put it another way, how well the engine/heads will operate the carb.
Lots of guys don't list their location in their profile. You are kind of shooting yourself in the foot IMO. While v8Buick's membership is mostly North America, it is worldwide. Help might be closer than you think, and you'd never know it. Be interesting to know how many members live outside of The North American continent. I would contact Ken or Mark to see if they would ship international, might be worth it to you. http://www.everyday-performance.com/ (techg8 on V8) https://quadrajetpower.com/ (carmantx on V8)
To also add to what Larry has said, there is a good chance that Mark or Ken already have the correct QJet core and you would not even need to send yours to them.
I live in Colombia (South America) and I think the few Buick owners I know in my city doesn't even actually knows that this forums exists I'm going to be in home in a couple hours, as soon as I get there I'm going to check my Qjet serial number and post it to see if at least is there any chance of work on my engine I should have some pics of the car, it really needs body and paint work because was neglected in the past and has been stored since 1988 until I bought it and get it back to life. Let me see which one I can share He can ship to Florida and then I can make it arrive to my home, I'm going to take that in mind as an option in case that my QJ is junk
These are the photos of the QJ that was on the car when I bought it, according to previous owner he only did 150 miles since he bought it in 1985 and never touched the carb (yeah, really exotic collector that bought more than 100 cars and stored them). I replaced carb gaskets, needle, needle seat and accelerator pump just before the first start so it was like a "partial" rebuild to my knowledge Destroyed idle tubes and down channel restrictors #17058213 - 1978 Four Barrel Chevrolet Manual Transmission Quadrajet The story behind the idle tubes and down channels is that when I first fired the engine the idle was fine but was too lean (If I put my hand over the air horn the idle speed increases like 300RPM) so I left the carb with a guy that somebody recommended me, told him to remove the tubes and well... things went wrong trying to remove them
Josehf. You need to go into Account and fill in your signature.. For all I know is you have a GS ??? 350 400 455 with a 4sp Hint,,, year car motor trans gear ratio. ETC Where you live helps also...
Actually I have the info on my profile so I'm not sure why isn't showing up My car is a 70GS 455 4speed Muncie m21 2.93 gear ratio with 26.6" wheels in the rear. Also I'm located in Colombia (South America)
