Jikov, head & barrel are the correct 73 parts from the bike.
When my dad bought it there were 2 almost complete sidepipe motors included with 1 of the top ends fitted due to the radial head & barrel having a melted piston, we were told someone forgot to take out the warming up plugs. I'll see if I can find the piston next time I'm at my parents & take a photo
Have been looking at what is missing or needs replacing in the sidepipe motors & plan on rebuilding them fully as I have the time/money, will probably use the top end that I had the liner out of as it's had the exhaust ports winged & the bore is perfect although the liner has had part of the spigot broken off & repaired