I run the 75/90 in my Cobra Toploader and have for over 10 years. works well on the track and off.
In my Daytona Coupe TKO 600 I removed all the fiber syncro's and replaced them with brass and in that trans I am running Castroil 30W engine
oil. At least for now. I may go to 50w
oil when I get it on the track after break in.
Clois