Speedo gears for the early trannies are no longer being produced (unless that's changed since I last looked), but you can find one every now and then on ebay or at swap meets.
Brewer's has new speedo gears. I bought one last year for my 65 vintage B&T A833.
Speedo is within 1 MPH at 70 according to my GPS.
Nobody talks sbout the B&T trans having a ball bearing tail housing compared to sleeve bearings in newer ones. NASCAR teams used them into the mid to late 60's.
