Oh yeah, forgot about the big valve, small bore issue. At 4.125 inches, a 361 bore is 1/8 inch (.125) smaller than a 383 bore. That's .060 on each side. Not that anyone would try it probably, but that might be small enough difference to clear. Especially if the 361 was bored .030 (now .045 on each side less than a 383) or .060 (only a .030 difference on each side - just about the same bore as a stock 413).
I have 2.14/1.81 Eddy heads on my .030 over 413 (4.22 bore). They clear that bore.
4.125 bore? Maybe not. And the 350 has an even smaller 4.0625 bore than a 361.
OK, this is all a pretty useless digression from the OP's original question.
