I haven't converted the 77 yet but I plan to very soon. Sean said to get a hold of him before I do for his recommendation of gearing but I haven't heard back from him yet. I'm leaving for the east coast in a week and a half so I better figure it out soon!
What a sweet score, Matt. Very nice!
I wrote you a message back with links and everything, but before I could hit send the computer pooped. Had to leave and thought I'd get another message off later, but......
Anyway, the short of the message was- I use JT sprockets straight out of the PartsUnlimited catalogue available at just about ANY motorcycle store or online. Exactly the same stuff you probably got for the 75 SS as it's listed for the 69-76 Honda's. 17tooth front/48 tooth rear keeps it pulling strong from a stop and through the twisties. If you want to do long freeway hauls and keep the revs down you can go with a 18 tooth front, but it's kinda sluggish taking off from a stop and not as quick on the power coming out of turns. I keep a spare 18T handy, but use 17T for most all occasions.
I've read here of people having trouble aligning their conversions i.e. having to shim this, or shave that, but the JT sprockets were a bolt on for me, and my alignment is spot on. There ends up being a small gap between the final drive output shaft and the shoulder of the front sprocket, and I put a washer in there as a spacer, but I'm not even sure it's necessary.
If you want to come by on a weekend to put on the new chain, and tune the bike for your trip you're more than welcome to. Otherwise, have a great trip and I'll give ya shout next time I'm riding out to Skyline.