Look for a number on the upper right hand side of the choke horn. You have given me a casting number on the main body. Look on the choke horn. 4160 and then another number. It is a vacuum secondary carb by the picture.

Dave

i cant find that number for the life of me i was looking for about an hour im kinda thinking just get a new carb or bring it to the carb guy and see if he knows what it is if i end up going with a new carb you have any suggestions? thanks
Gary

Holley 750 vacuum secondaries electric choke 4160 0-9015-0; 502 cubic inches max rpm 5200 ought to do it.

Dave

thanks alot why vacume secondaries ? just outta curiosity

It looks to be a boost referenced carb too.