On most if not all 2-barrel and 4-barrel carburetors the part number is located on the front left (driver's)side of the air horn.
You will need an adapter to coveg the EGR crossover.
so far I found OEM#4049393
a webber, is a type of holley carburetor.
Holley 4180
There is no reason you would have to.
holley 4150 c
Clean the side of the carburetor above the air horn or choke tower using a wire brush for degreaser. Locate the part number listed on the side of the carb. It will start with an "R" followed by either four or five numbers, and possibly a hyphen and a single digit. Look up the part number in the Holly part number reference guide. It will tell you everything you need to know about the carburetor, including the model number, CFM, and what replacement parts it uses.
Yes, it's the Holley 1940. You can get them from Champion Carburetor.
I would recommend finding some carburetor books to read. People have made careers out of this question and it cannot be answered in a few sentences or paragraphs. "Holley Carburetors & Manifolds" published by HP Books is a good place to start. Kyrasis6 Mazdatruckin.com
A small one with vacuum secondaries.
Very little, if any at all. The carburetor is not what makes the horse power, The rotateing system and Valve train is what makes HP.
The phone number of the Murray Holley Historical Socty is: 585-638-7566.