It won't start, not even with TWO new fully charged batteries connected to it, without a boost from another vehicle. All of the electrics are new and properly installed, the starter is correct for a 10:1 Pontiac 350, when the starter is installed on another Ponty 350 it'll spin over fine, additional grounds don't help, bypassing the solenoid doesn't help. All the starting parts are new GM or Mallory made parts. Timing and mixture are correct, etc., etc., we've swapped parts with a known good car, etc., etc. It just won't start when cold or hot without help.
My Pathfinder boosting the Firebird:
