It's a 383

I measured the stroke at 3.3 and that makes it a 383 just like you figured with the red valve covers.

My interchange manual says the intake, carb, exhaust manifolds, rods, cam, heads, timing gear-chain are the same as my 430 but it lists different pistons and block. How can this be if both sport a 4.3 bore?

The crank fits ONLY the 383 but can I install a 430 crank and get a 430.... that's something I need to research.

Thanks,

Dave
aka
J-Bird430