Quadrajet on My 77 Chevy Silverado C10

[oscarlovel]

Just bought a 1977 Chevrolet C10 with the 350/350 drivetrain and the F44 option. I understand this is the equivalent to the Heavy Half GMC that I purchased new in 1979. I've had carb issues since I purchased the 77 a couple of weeks ago. Takes a bit of cranking and several priming pumps of the accelerator on a cold start (not exactly cold as the temps here in north Louisiana have been in the 90's and 100's lately). The carburetor is a Rochester Quadrajet 7045583 7Z and this checks the reference material as possibly being the original carb. It has a divorced choke on the manifold that appears to be mis-mounted with a block between the choke and the manifold, and there is no linkage connected to the carb itself. Also, the choke plate is entirely missing. When it warms up, the carb seems to function fine, but I know winter is not that far off. I thought about an Edelbrock 1406, but I've managed to lay my hands on another 7045583 carb that is complete. I'm pondering scavenging the choke plate from the spare carb and redoing the divorced choke or doing a conversion to electric choke. It's been a while since I have worked on old vehicles and would appreciate your recommendations. This is essentially a stock truck with 72000 miles and a back up daily driver.

[JohnnyPopper]

Since heat/weather is not an issue right now, seems like you are suffering from what a lot of us do.

Gas in the float bowl evaporates when parked, and with some, the gas in the feed line gravity feeds back toward the tank.

A simple fix is an inline check valve. Since you already have rubber in the line, should be an easy add.

I would marry the two so you have the benefit of your choke in coming months.

BTW, that springy-spring does not look stock. Most I've seen have the heater tube that drops into the manifold...

[bd]

How many gaskets are stacked up between the carburetor and the manifold?  I'll bet the block is there to compensate for the increased height.  The choke thermostat is missing its stamped metal cover.  You can fabricate a replacement choke stat link from an appropriate diameter welding rod.  Why don't you rebuild the newly acquired (complete) QJ and then swap it out for the existing carburetor that is missing the choke plate?  That way you won't have to fret over damaging or twisting off the choke plate screws and you'll have transportation in the meantime.

QJs are not difficult to overhaul, although there are a few tricks and simple tools to hedge success.