Hard Starting Hot Big Block

I'm out of ideas on what could be going on with my Dart and not wanting to start.

1/0 Copper welding wire from the trunk mounted battery to a 300amp circuit breaker the up to the front of the car on the driver side fender. I also have a 1/0 cable up to the front for ground as well as a 1' long 2ga wire from the battery negative to a grounded to metal spot on the wheel well. I have a 1/0 copper welding cable from the negative line I ran to the driver side cylinder head.

What I've tried:

Bypassed the circuit breaker from the battery to the front (nut and bolted the wire together, no difference,
Put the power wire to the starter and from the battery on the same post up front, no change
New MSD Starter, no change,
New starter relay, no change
Added another ground wire from the starter mounting stud to the fire wall, no change.

It drops to 2-3v when cranking per my Edelbrock Pro-Flo. Base timing is set at 12 degrees per what edelbrock calls for with their EFI system


440 stroked to 512 10.5:1 compression hydraulic tappit cam, Edelbrock Pro-Flo EFI, intank Tanks-Inc Pump, MSD 6AL-2 ignition block