Just remember, only doing the ground mods without neutralising the corrosion on the MPU won't be enough to get you a reliable game.

A guy called Fred, fretto1@gmail.com has recently remade the whole sys80 board range, 80, 80a, 80b.
http://m.youtube.com/watch?v=k8AiGRQV_aQ

or pinball resource have NOS 80b boards.

Or send your board to Beaky as Ken doesn't accept Gottlieb boards.