Bore and Stroke for gen 1....

327 = 4.000" x 3.25" (Gen.I, 5.7" rod)
350 = 4.000" x 3.48" (Gen.I, 5.7" rod)

Now you can use a 327 crank in a 350 if it's a " Medium" journal 2.45" which all 350's are.

The "Small" journal is 2.30" and while they do make spacers to use these I won't chance it.