The other thread is this one:
My post was aimed at Loco simply 'coz he's already asked the corrosion question last week.
Basically went to change the thermostat, sheared 3/4 bolts on the housing (with virtually no effort whatsoever), found they had welded in to the point that a week steeping them & heat & all the other usual thread extraction tricks didn't work, so went for the helicoil fix, and basically stripped one thread in the head with nothing more than a helicoil (still on the insertion tool!)
Thanks for the info, I am aware it shares bits with a lot of similar sized yams (I believe sizeable chunks of the leg / clamp are even interchangeable with the 3 cyl autolube machines). I have sourced a shop who specialise in older engines, who tells me he has a couple of them that are only in his "dead shed" due to meeting the bottom at speed. (i.e they died from a terminal gearbox impact). I guess fortunately for me, it was probably cheaper to replace than repair. Work's been getting in the way the last few eves, but will hopefully have the head off by the end of the week & find out just how terminal the corrosion is. I'll make the decision after that.
It's a '78/79 vintage