there is an "early" & a "late" cast iron 440+6 intake - casting number 2946275 VS. 2946276 (& then a third design with the same 2946276 part # on it between the carb mounts)
I've heard rumors about the first design being "porous" or some other casting flaw causing Chrysler to purchase every aluminum intake available at Edelbrock to keep the engine assembly line moving while the intake was being redesigned/reconfigured

the 1970 model year started production with the cast iron intake & in the time gap between "275" & "276" manifolds is where the aluminum manifolds are found during 1970 engine production

I've seen a number of November scheduled cars with aluminum intakes, but more importantly would be the engine assembly dates, when the engine was assembled at the Trenton engine plant

the first design "276" intake has a casting/parting line down the center of the manifold

who has access to a 1970 440+6 car with its original engine and an aluminum intake? what's the car's: assembly plant, SPD & engine assembly date?