I too had visions of a CAT D9G or something like that.

I'd gut the electronics and measure up it's insides.
Someone on here will measure up HL boards for you and tell you what bits you need,say non S&S boards and transmitter for simplicity,tell you how to wire them up and away you go.

There's plenty of the guys here who've converted non-S&S tanks to S&S so you might get their old boards and transmitter for the right price if you ask nicely.

Miggers [8D]