Howdy Ed:
The gasket you referred to from the Handbook is the composite type FoMoCo replacement. The "A" suffix is a big question mark, but not an eliminator. It the seller can verify that the bore or inside diameter of each cylinder hole is 3.81" and is .037" thick it will work and it proves, once again, that with FoMoCo, never say "Never" or "Always". I'd sure be interested to know what this gasket is.
Let us know what you find.
Adios, David