My thoughts are first of a deficiency in the cranking system.
Does the starter spin the engine in a normal lively manner when the spark is interrupted by disconnecting the switch wire at the dist.??
Second thought is that the 8 deg static advance(probably 4 is spec)should mean no problem to a 283 unless you are setting from a balancer which has incorrect reference marks and the 8 deg indicated is actually 20 or thereabouts.there are a couple of reasons the references could be in error and a quick and easy ballpark check could be done by feeling the piston position along with viewing the valve overlap on the #1 or #6 cylinder.
Have you been listening when Jerry talked about using the valve overlap @ TDC to check cam timing, TDC position, and a reference position for valve adjustment?
If we are going to be doing engine work and troubleshooting engine problems we need to get a good grasp of the overlap at TDC thing as it can be a powerful problem solving tool as well as ready proof when cam timing comes in question.That goes for gas or diesel from Acura to Zetor.

Bob Taylor