Sounds like you need to check the timing. If it's not hitting near TDC, it can act like that.
Also, try putting your hand over the exhaust pipe and feel for pressure coming out and at the carberator intake, feel for suction. If it's sucking gas/air and you have compression and the spark is near TDC, that engine should start.
One more thing... firing order on an AC-B is different than International tractors. The correct firing order for an Allis is 1,2,4,3.