I have a brand new set of 341s that are going on my K6 real soon. Like you, I needed to scavenge for a long time to get all the pieces parts (studs, collars, kickstand & centerstand stop, long bolts for footpegs, heat shields, etc.)
I'm just ready to put them on and I make a barn find that could change it all. I found a K0 with an apparently good engine. The bike was literally "hatcheted" into pieces. It seems a young lad wanted to make a go-kart. Well, he picked an excellent engine - I'll give him that. He later lost interest and now I have a pile of K0 parts.
Here's my dilemma: Do I replace the engine in the K6 with the mystery K0 engine (ser# CB750E-1038053, 21K miles). The K6 engine runs nicely at 40-something horsepower and 18K miles. I'm told the K0 is significantly nicer on the HP front

Back down to earth for a second - I have to do a compression test on the K0 engine.
I cannot wait to hear the HM341s on
either engine.