Thanks Puckle, you saved me a lot of time with that. I considered buying a Blue Sea dual load path unit, but plan to use just one battery and run everything off the same load bus. One difference is I will remove the non-functioning speedo and replace it with a tachometer which I believe will be more useful. And an oil pressure gauge - there's no oil pressure gauge on this machine, just a low oil light.
Mine does not have the warning plate stating "Do Not Turn Wheel...". Also need a new floorboard, I'll go back in with marine plywood, epoxy edge=sealed and coated. Looks like Triumph TR-6 windscreen wiper mechanisms. The little blue light above the turn indicator switch remains a mystery. Those murderous cross-headed screws with their frozen nuts locked in place with Nature's Loc-Tite are driving me nuts - I'm having to cut them off one by one and no amount penetrant or cussing will get them off. The entire machine is assembled with those infernal fasteners.
Transmission coming apart to clean out all the old black oil, it does not have the strong smell of gear oil, looks more like engine oil and there was not much left in it. Gears, bearings and ring&pinion look very good, so I'll clean it up and get it back together with new seals. I plane to use Redline lightweight shockproof gear oil (same as in the Hewland on my race car) because it clings to the internal surface like glue and does not drip off gears or bearings - even after sitting all winter - perfect for an intermittent use application such as the Snow-Trac.
More indication of this machine's Mclarty origins is this fire extinguisher I found still mounted under the seat, manufactured by Vanguard in Norwich - and it says on the back I can send it back to them in Norwich after the 1999 expiry date and they would refill the bottle for half the retail price
Still have not found a serial number anywhere. -still looking.