When I bought my rusty 76 TR6 in 1990, the motor was froze up. I tried most of the above to no avail. Finally, I pulled the head and found the #6 piston had taken most of the abuse of water entering the intake through the carbs and running down hill to #6. With the head off, I was able to soak, tap, and ultimately pound with a huge hammer and a block of wood, still to no avail. Finally, I rigged up a breaker bar to the front crankshaft bolt with a 6 FOOT piece of pipe for a cheater and pounded it with a 10 pound splitting maul. This is the truth! No BS or false memories here. The piston finally moved about 1/64th of an inch. Once it moved at all, I knew I was home free. Upon rebuilding, (I was a driveability tech at a Chrysler dealership at the time) the old timer heavy tech told me to clean up the bore with a glaze breaker, put new rings on and "forget it". Having no money and a huge project on my hands, I took his advice. I drove that car for 16 years and about 50,000 miles. Never a problem, other than 2 sets of crankshaft thrust washers. I always thought the crankshaft would break in two someday, but it never did.