1974 D300 360 fresh rebuild will not start

I was talking about the argument over "6 and 12" Sorry I should have worded that better. I agree it could be the cam is OUT of time.

For me there is ONLY ONE CORRECT WAY and that is to align the marks BY THE BOOK or degree it if you have the cam specs
Ok then I totally read that in the wrong context, all good on this end.
I'll do a teardown of the water pump/timing cover/whole damn front after work today.
When you get it apart post some pictures, just curious about your key way orientation.