This is a 1937 Triumph T70 Gearbox which was rebuilt due to a failing bronze bush on the main shaft. I've seen online a few people expressing difficulty in regards to the cam plate position which allows you to selects all gears correctly. Failure to line up your datum's means multiple strip downs (Which no one wants!)
I hope this video will help you in every way !
Regards YoungOldJoe

P.s - Upon rebuilding I soaked all the gears and bushes in good quality SAE 70-90 oil to ensure smooth lubed running from the get go!