WRRS Model 5 Wig-Wag restoration question

[CNW_FAN]

Hello, our museum was recently donated a wig-wag signal. I am in the process of restoring it and have found just about all the parts I need. The only trouble is, I can't get the cast harp base off the pole! Our museum has opted to display this signal indoors for now due to it's rarity, but the original pole will not work because the ceilings are too low. I will be constructing a separate pole and base for indoor display. Any suggestions on how to get the harp base off the pole? The 4 pinch bolts have been cleanly removed. Any insight would be greatly appreciated. I have soaked it in PB Blaster and also tried using heat from a propane soldering torch on it. I will probably need more heat than that, but I don't want to ruin the casting by heating it unevenly. We have also hammered away on it using 4x4 wood blocks, but it will not budge. There is a gap between the pole and casting about halfway around, but the rest is stuck to the pole somehow.

[CNW_FAN]

Tried installing it in a rig at work and using hydraulic force to separate the two, but that did not work. At that point I determined the pole is too far gone to save and cut the pole right below the harp base and will cut and remove the pole that way. Same with the base. Thanks anyways.