No start 95 sport nautique

Hi all, looking for some guidance with my 95 sport nautique. Had to replace the engine with a new crate 351w from summit racing. It cranks with 40psi of oil pressure, I lined up the mallory electronic distributor with cyl 1 on the compression stroke, even rebuilt the Holley carb. I CAN NOT get this POS to fire! Best is it'll start to fire and immediately choke out. Pulled the plugs and they don't look flooded so I'm thinking there is not enough vacuum pulling into the combustion chamber. Sure enough, reading 0 on manifold vacuum when cranking. A compression test shows 60-70 on most cylinders, a 35!!, and a couple 100s. Im hoping the low readings are from the rings not being seated on a fresh engine.
Anyone have any ideas? Leak down test would be my next option but it's raining here and the ski tower has me sticking half way out of the barn.

I’m not a Ford or Winsor engine guru but I’m sure it’s the same as with a Chevy engine. When lining up the distributor cap with number one cylinder on compression. You’re too far advance. It won’t fire up unless you set the timing back a little. For me when resetting the timing for Before Top Dead Center (BTDC) after a rebuilt or pulling the distributor, I have somebody cranking the engine while I’m adjusting the distributer to get it to fire up. Then I set the timing accordingly for that engine.