Sorry to take so long getting back to this!
The compression post is 52 inches tall, 1 3/4 x 1 1/2
The port bulkhead attaches foreword and is cut in.
My mast step is thru-bolted with 1/4 inch bolts. I believe mine has been replaced at some time. This style may be available through D&R marine. (no affiliation)
The mast is down right now and the blocks are there to support a tarp tent over the boat.
Hope this helps.