Heres what's been rattling around in my brain when its not pushing hair out the top of my head.
ORF has these m76 kits with no barrel or reciever but lots of other goodies.
previous posts pictures and compairsons show that the differance between a 308 yugo and a 7.62 are in the bolt and carrier not the trunion which seems to be the case with the Faz family rifles.
If you look at the chamber area pics you can see the .308 is not pushed as far into the trunion which give you the room for the extra cartridge lenth on that rifle.
The 8.mm rifles look like they have longer recievers but that shoudn't be too hard to do.
so the question is will a M76 bolt fit into a M70 trunion? if it does how hard would it be to do a M90 clone which is basically a stamped version of the M76/77 milled rifle. using M70 trunions