Incomplete HEI conversion...what to do

[Siedl]

Hi! I just picked up a 72 gmc stepside and from what I can tell they attempted to convert to an HEI ignition but didn't change the distributor, left the vacuum hose detached from the carb and hanging, unplugged and didn't change any of the spark plug wires.

The truck has started randomly dying, today going 40mph. My research tells me it could be timing or carburetor but wonder if it could be the unfinished conversion/possibly the vacuum hose that's just dangling there.

Any guidance is appreciated! Thanks in advance!