Redline motorcycle gear oil. It's good quality stuff it's been in stock trans, no gear noise. I talked to Arlan, he hasn't noticed it on the dyno but with ear plugs/muffs on and all kinds of tire noise etc, it would probably be hard to detect any gear noise.
I am going to run and see what happens, and like I said in the beginning, this is not a bash post I'm glad someone is willing to make parts for a 30+ year old machine to keep them running. Without them, we wouldn't be riding them any longer. I'm sure with the thick heavy shift forks, along with the completely new gear set, there's going to be a break in period.