My current project isn't a Mopar, but a 1951 Chevy Truck 3100 w/216 inline-6 and 3-speed that's been sitting outside for over 30 years on an old farm in east Kansas. Put MMO in cylinders that were stuck. 2 weeks later, I was able to break them free. Found valves/lifters stuck open. Gain, squirted with MMO & PB blaster, a few hand cranks and a small rubber mallet, they are now all moving freely. Plan on firing the motor over this next weekend.

Another farmer trick is transmission fluid and diesel mixed together for penetrating fluid. We had a stuck Model-A John Deere and it freed after sitting a month with the cylinders filled with it.