Re: Quadrajet questions
I think q-jets are very good carbs for street use. They have always worked great for me when set up properly.
You may get some different ideas here, however I do not see any reason to remove choke blade for street use. If it were a race vehicle, that may be a different story, but I'm sure a race carb would be the way to go for that. As a technician, I see parts removed like that from those not performing the correct repair to the vehicle, instead someone might remove parts thinking it may help something.
Choke should be put back to working order in my eyes.
Secondary air valve or flap at top opens by the engine drawing enough air through it when the secondary throttle blade is opened. Normally if there was no way to delay the opening of it your vehicle would lose power from opening too fast. So, the linkage you see that has the diaphragm and hose on it... That keeps the secondary flap from opening too fast. At wide open throttle you start losing vacuum to that valve and it will allow the flap to open slowly.
You need full manifold vacuum going to it. Normally that hose gets plugged in ti the port right next to the diaphragm that you have plugged off. If it is getting full vacuum then its ok. With the engine running at idle the linkage should keep that flap closed.
It may be hard to get the flap to open just by reving the engine, the vehicle need to have a load. That flap also is what allows the control of the secondary metering rods to allow the fuel to the engine. (opens the jets in a sense).
It may run rich, due to the carb not being original to the vehicle, smaller jets in the primaries may help. Idle system has air passages and metered orifices that all work together.
Those year carbs are nice in my eyes, they are the ones I run, even though they are not correct for the year, or stock resto type.
If it were me, and having the parts to do the repairs, I would try and get that carb back to working order. A much easier solution would be to have it replaced with a similar carb. You can put the correct year carb on, or get a rebuilt, or new q-jet, or go after market.
For an easy job and fix, I would contact a shop that specializes in q-jets and buy one that is set up for your vehicle. Then the jets, metering rods, idle circuits - should be all set up nice.
There are many ways to go about getting a new carb, to me driveability is important and why I like good working Quadrajets. Some do not...