1974 D300 360 fresh rebuild will not start

Hey everyone, thanks for all the useful tips and pointing me in the right direction. I haven't gotten a chance to tear her apart yet, I run a small business and I've been running around like a chicken with my head cut off.

When I checked the cylinders for leakdown I used a metered air source from my air compressor (which I also used to confirm that my gauge is right, unless they're both wrong and reading the same thing.... :/ -that would be my luck, seriously)

I'll get to work taking off the accessories so I can get to the timing cover, take some pictures and keep ya posted! Thanks again!