I have been working in my fathers old bike. He bought it new in 1973. When he purchased it he also picked up a "hot cam" and a smaller front sprocket. He is pretty short so he lowered the rear and swapped out to a 16 inch rear wheel. He did the lowering project but never installed the cam.
In the early 80's a cousin (Zeek) purchased the bike from him. Zeek ditched the lowing blocks and installed the cam. Somewhere in there the sprockets both were changed as well, back to stock. Then in 1990 he parked the bike. It sat until last summer when I purchased it.
I don't know when the exhaust was changed, I'm assuming that Zeek did, but I forgot to ask him.
While the bike was parked the roof collapsed on the barn it was stored in. The roof twisted the sissy bar, the very back tail of the left side of the frame, bent the handlebars, mangled the gauges, headlight and top of the triple tree.
As luck would have it I was also able to purchase a donor parts bike this summer off craigslist. This gave me all the parts that I needed.
Sorry for the long story, but that's the history as I know it.
Now that I have the bike I'm just hoping to get it functional, not necessarily a complete resto.
Here's a picture of when I picked it up, and what it looks like now (parts bike in the background)