well after further looking there is another set of numbers on the back side of the air horn. 74481 with 1674 below those. my CARQUEST guy could not pull them up though he thinks it may be some type high performance 2 BBL. he said he'd make some calls but at least he says he can get me a accelerator pump diaphragm for the base which is leaking and probably I better get a power valve also. I have been told they are bad to blow out as soon as one backfires with a Holley. I can't really tell if it is bad. most likely this is not an original carb since it has an adapter block bolted to the manifold- but I want it to run for now and likely I'll try to get a propane system to install on it if I drive it much. Raymond