I recently got two Model a's and lucked out the 39 model has a heisler head and the 42-44 model (steel serial number tag rusted) has a powerblock. Im wanting to build a puller out of on of them. What would be the best setup? Was hoping to put the heisler on the 42-44 model but don't think you can because of the added stroke unless you mill the pistons down. Anyone know anything about it?