If the vacuum advance on the distributor was plugged, but the hose was open, then the engine was probably running at higher rpm.
The initial timing must be set at the specified rpm.
If its too far off, then it can makes starting more difficult.
So there's another possibility. Hard to know if its what happened but figured I'd mention it.
I usually remove the vacuum advance hose at the distributor and stick a golf tee in it.
With the slant, might be slightly easier to pull the hose at the carburetor and put a cap on the carburetor port. Either way will work.
