A: This info is from a top AMC guy:
From: Randy Guynn <amx69@swbell.net>
To: danritz@coredcs.com, mail@amc-list.com
Subject: Intake manifold part 

Dan,

If that is the casting number, it will be ONE number off from the part
number. There is basically 5 different cast iron AMC factory 4 barrel
intakes.
#1, standard 1967-69 models. The intake bolts dip way down and are hard
to get at right by the carb in the center 4 bolts it will have 4 round
holes on the carb flange
#2,1970 & 71 standard 4 barrel intakes, it has the center 4 bolt holes
higher and easier to get at than 69 & earlier models, it too will have 4
round holes on carb flange
#3, 1970 Rebel machine intaske, it has to ovel holes on the carb flange
and it was not always on Rebels, it also came on 1970 & 1971 big engines
in the Ambassadors and on some Jeep truck models.
#4,  1973 and later spread bore 4 barrel intakes for spread bore
motorcraft carbs
#5, 1973 & later Spread  bore 4 barrel intakes with EGR provision.

That just about sums up cast iron AMC 4 barrel intakes. The casting
number IS NOT the part number. If this is a Rebel Machine intake, the
casting number is ONE off of the part number. Give a look at the intake,
you should be able to tell what it is by the info I provided.

Thanks,
Randyu Guynn
performance American Style