I was told by the original owner of my car that he changed the carb to a Holley in 1972. The other owners have said they made no changes. So I thought I had a Holley to replace. I've actually taken a closer look at it, and low and behold it's a Q-jet. It has a decal "re manufactured by Holley" stuck to it. The numbers are not correct, so I could use some help identifying it. Here are some pics. Looks like the 37th day of 1971, but I can't find the number to ID the carb.
Thanks for any tips,
Greg

 

7041206 was original to a '71 Chevrolet/GMC 20 & 30 series pickup with a 402 big block.

 

OK, thanks.... so now I guess I need to know if I can make this one work properly on my vette. Or should I go ahead and find the right numbered unit?
Greg

 

All the connections are right- fuel line, choke linkages, and vaccum lines. Good enough. Either rebuild it yourself following Lars' papers or see if he's back and send it to him..

 

you might want to start with a toothbrush & some gumout........

 

Lars papers can give you the info on correct jets and rods and specifics on best rebuild methods. Unless Lars knows of some specific reason why that unit won't do the job for you, I believe it can be rebuilt to serve your needs just fine. Of course, it won't be exactly like the one on your car when it left the factory, but it should work perfectly well. My best advice would be for you to send carb and dizzy to Lars for him to rebuild (when he gets back on the mend); but if he's not feeling up to it yet, he may be willing to advise you during your rebuild of it. e-mail him at V8fastcars@msn.com .

 

Thanks guys,

In the meantime, can anyone tell me what this part is? Looks like a pump but I haven't any idea what it should be hooked up to.
Thanks,
Greg

 

I haven't seen one those in a long time, they were usually removed and thrown away because they effected performance. It's called a Transmission Controlled Spark Solenoid, used on all GM cars from 1970-1974. It was installed to reduce hydrocarbons at part throttle cruise by shutting down the vacuum advance in low gears when the engine is at operating temperature. On a 4 speed car vacuum is shut off in 1st and 2nd gears. There should be a switch with one terminal on your transmission that connects to one terminal on the solenoid, The other terminal connects to a relay that I think is mounted on the firewall and the relay is controlled by a temperature over ride switch that I think is on the intake. The relay is fed power from the ignition circuit. Manifold vacuum is fed into the solenoid by the electrical connector. The vertical vacuum port goes to the vacuum advance and the remaining port is just a vent and goes to a open port on the top of the carb air horn. Before you hook it up you'll need to test it to make sure the plunger inside works. I know you want accuracy so what I would do from a restoration and appearance standpoint; connect everything by the book but remove the plunger inside and plug the vertical outlet with epoxy. This way the vacuum goes straight through and you have your vacuum advance all the time.

 

Exactly. Good tip on how to deal with it and keep the car looking original.

 

Great info! Thanks much...
Greg

 

Greg,
I believe that a solenoid that looked like that was used in 70 and 72. The 70 # was 11114432 and the 72 was # 11114451. Does your have a part # ? You're lucky to have it since they're usually long gone. Keep it even if you don't use it now.
Regards,
Alan

 

Thanks, Alan. Looks like I've got the right one:
Greg