I suspect the 701 number is just a casting number on one of the body parts, the important number will be on a small brass tag held by one of the top screws, it ID's the exact carb [tags frequently long gone] - a 'GM 2 jet" is the common Rochester 2G, a 2 barrel not a 1 barrel, look down the bore and you'll see 2 "barrels"
the number "on top of the engine" [on the intake manifold] is the manifold casting number of a 2 barrel intake,
like this one, a correct original
Bill
