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I am a little confused as the first four digits indicate this is a Rochester 1970 carb. the last three digits allways gets dicey at best. If I am correct on the date, I did not know California had different standards in 1970 than the rest of the nation. Again, you learn something everyday.
From: At my Bar drinking and wrenching in Lafayette Colorado
Your 7040511 is a California truck carb (1970 350 Truck). Both this truck carb and a 1970 Corvette carb 7040207 have the same jet/rod combination of 76/44, and they both use the same secondary metering rods. The carbs look pretty much identical, and they use the same airhorn assembly (top of the carb). The difference between the two carbs is that they use different float bowl assemblies and different throttle body assemblies, so the air bleed and fuel restrictor orifaces are sized differently in addition to differences in throttle lever configuration. These changes in the internal orifaces are what make the CA carb different.
You can set up the truck carb to run just fine on your Vette. Start with the baseline jetting and tune from there based on what your engine needs. But you'll never end up with "exactly" the same setup as the Vette carb due to the variations in the fuel and air metering orifaces, which are not replacable.
Please help me ID my Q-jet (17066559) this number doesn’t seem to conform to any chart I’ve seen.
...and from everything that I’ve read, I assume that it’s an M4MC
One site says that it’s off an Oldsmobile, while another site says that it can only be off of a Cadillac, GMC, or Chevy. and I can’t determine whether it’s federal or California.
and the only (year) interpretation of any code i’ve seen is 1976.
I have a 1986 GMC sierra classic 1500 4 x 4 that has been Frankensteined.
The engine is a 1980 from a 1 ton California van, made in Canada, but I am positive that the carburetor is not from this engine. The intake manifold does not have the hot air port for the hot air choke intake.
Most of my issue is related to choke problems because I live in Alaska, where we have extreme cold temperatures. I have disengaged my choke, because it never turns off, because I have no hot air intake for the choke to warm up from.
I assume the 4 digit code says that it was made 322nd day of 1975?
From: At my Bar drinking and wrenching in Lafayette Colorado
You're opening and responding to a thread that is 13 years old... best to open a new thread rather than trying to revive one from the dead...
The real answer to your question is, "it doesn't matter." From that little section of the carb shown in the photo, your carb is one of the dreaded, hacked, trashed commercially rebuilt carbs. It is complete junk, and not worth any time or money attempting to save. Simply throw it in the trash and find an unmolested rebuildable carb that has not been destroyed by a commercial builder. Before it was destroyed, that carb was a Service Replacement carb for an Oldsmobile, and the carb was built at the end of 1985, which is a 1986 production year.
Quadrajet Model # decoding question
