I got the chips a while ago, and worked on the game tonight. I got the new Z80 onto the HSS kit, then went to put that on the board. The HSS kit didn't fit in the original Z80 socket on the board. Luckily I got a replacement socket with the kit. So tonight I desoldered the old socket, and soldered in the new socket (and I am NOT a great solderer). More @Wikipedia
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