I welded a socket into a box end wrench, to get at the bolts, i would have to go look at what i did, or take a picture. I will say it worked well. Had to replace a seized one about 5 years ago.
After I got six pistons out and the main caps off I got it to turn enough to get at the last two rod caps.
But it still turns hard...need a big pipe wedged in the damper
Makes me think the cam bearings are seized. Might have to get out a bmfh to get that out...out to the shop soon.