383 magnum versus 383 big block

toolmanmike said
I used 1.800 int. 1.600 exhaust valves. I didn't look up the stock 383 valve size. Their intakes are possibly closer to 2.000" but I might be suprised.

383, depending on the head castings, should have a 2.08 and at minimum a 1.74 exhaust, except for the early heads which were a 1.60 exhaust.