C1SS,
I don't think those photos are of a "Mystery Motor". First of all, those motors were not sanctioned to race in anything in '67. Chevy never made a 3x2 intake for one (although Smokey could have made anything). There were no aluminum heads or water pump ever noted for that engine. I've never heard of a set of 4-tube headers made for that engine. Nascar required factory exhaust manifolds in '63. IF you look closely at the front of the intake, it doesn't have the same shape as the mystery motor. (scroll up and look at the shape of the intake I posted and compare) It all looks like a MK-IV to me.
Just my opinion.
Verne