4.0L HO Jeep Engine Build

Wow that sucks about the cam, but is it really connected to ignition advance in such a 'direct' way? I haven't opened up one of these engines yet but would it be possible to perhaps just advance the cam without touching the distributor drive shaft, as in leaving the dizzy drive in one position but advancing the cam on its own? Also doesn't the phasing of the distributor on Chrysler MPFI engines like this one only control fuel injection timing? I know that's how it is on the Magnum engines from the '90s.