Very interesting modification. You bought it rebuilt? Did they just do bearings and synchros? I haven't opened this one up because it isn't suitable for my MG project. Surprised at the condition of these 38 year old 60 series transmissions I have. Also would you happen to be using the A12 mated to your 63 box? I have one of those motors also and hesitate to sell it because there are way more performance parts available for that engine. Might use it for another project.