I've heard that from many sources, but I don't think it's correct. This is from the wikipedia listing for "AMC V-8":
"Contrary to a popular myth, the AMC V8 was not built by Ford or anyone else. They did share some electrical parts (starter and distributor) with Fords, and some models used Motorcraft (Ford) carburetors, but the engine design is totally different."
There's no citation to look up there, but this has always been my understanding.