I'm still not quite ready to get back to sheet metal, so I figure I can begin assembling Old 99. Everything looks good and all the tolerances check out, so here we go!
Bare block.
In goes the crank.
Cam installed and timing set.

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Front plate and pulley.

Pistons and connecting rods, ready for installation.
The pistons were fun. In the 1275, the pin is an interference fit in the connecting rod. I used the power of the Internet and found a way to make my own press. A long, thick threaded bolt with two washers and grade 8 nuts, and a deep well socket (or a piece of pipe, but a 22mm works perfectly). Some assembly lube and a 1/2" socket, a couple of hours, and voila!