C3: Part number help. Quadrajet air horn.

[Richard K.]

Can someone (Joe L. ?) help me ID the application(s) for a Rochester Quadrajet air horn that I bought at a flea market with hopes that it would work on my carb #7029207. Gr. No. 3.730, #7034896.

Thanks Much
Rich Kossum

[Clem Z.]

Re: C3: Part number help. Quadrajet air horn.

the correct part # for a 7029207 carb is 7037332

[Joe L.]

Re: C3: Part number help. Quadrajet air horn.

Rich-----

Air horn GM #7034896 is applicable to Rochester Q-Jet GM #7028210. This carburetor was used on 1968 passenger cars with big block and automatic transmission.

Whther, or not, this air horn could be used on your 7029207 carburetor I could not say, for sure. GM never catalogued this air horn for SERVICE use on your carburetor, so that says that there must be some difference. However, most of these 68-69 air horns are pretty similar. I would check it out in 2 particular areas:

1) the idle vent. Your 7029207 should use an external idle vent on the front, top of the fuel bowl. You may find that the idle vent on the 7034896 air horn is different. There may be CASTING provisions for the external idle vent, but no actual hole(s) drilled in the casting. In this case, you might be able to modify the casting to add the idle vent provisions, using your old air horn as a model. You cannot use an internal idle vent since your fuel bowl is not set up for it. So, if the 7034896 does not have the idle vent provisons, you must add them or, for sure, you can't use it;

2) choke valve actuation mechanism. There may be slight differences in the choke valve operation shaft and lever mechanism. You will need to carefully compare the old set-up with the one present on the 7034896 and see if it is the same or close enough to use.

Otherwise, I would generally compare the old and the new for differences. If you find none, I would say that it's a pretty good bet that you can use it.

[Clem Z.]

the air bleed hole size could be different

and some Q jet have a fuel enrichment holes above the secondary air valve for quicker enrichment when the secondary opens.if you have both the difference should be easy to see.

[Richard K.]

Re: the air bleed hole size could be different

Thanks folks for the help. I'll check for those differences. If I can use it, I certainly will, otherwise, I'll try to get it to someone who needs it for their Chevy restoration.

Rich Kossum