when it gets hot - your clearances are probably getting tighter - makes it hard to start - check your rotating torque when cool then check it hot - that might give your answer

UPDATE

After a lot of testing over the last week I think we've finally gotten in front a few issues. The issue was the motor was running hot (220) and wouldn't crank once it was hot. So... here is what we changed or fixed.

- put two different batteries in the car with good amperage output
- added another heavy ground wire going directly from the battery to the bell housing
- replaced the starter with another Chrysler mini (the one that was on the car died Saturday a.m. (bad solenoid)
- added a 1" dia hole restrictor at the thermostat neck to slow the water
- put the old flex fan on it (just for testing)

The end result was a motor that doesn't get hotter then 190 deg and cranks very easily with 12 volts. Next thing is to find some electric fans that are up to the challenge. With all of that I also had a volt meter that was reading a solid 14 volts.

Thanks for all the input from everyone. Now I might actually get this thing down the track.

Nice upgrades!Early on I was going to say go to a 16v system but that would have cost a lot more and not really fix the cork in the bottle.Good job.