440 Engine Build w Timing issues

Two times I had an engine that wouldn't run unless I had 60 degrees initial. I was working on the distributor that had a magnet under the pick-up and I reversed the magnet. We swapped the wires going to the distributor and the timing could be reset to normal. The other time we had reversed the wires going to the distributor and as it was the same symptoms as previous we knew to reverse the wires. This maybe your problem, maybe not.