Lt77 gearbox identification help

[llohcins]

Hi all, I did a v8 conversion on my mgb gt a few years back, it’s got an lt77 gearbox in it with a standard clutch kit but it can’t keep up with the bhp and torque that the car is producing now. Because of time it going to ask a garage to install an uprated clutch for me and the uprated clutch is a 10day turnaround time from ordering. My problem is I am trying to confirm how many splines are on the input shaft of the gearbox without taking it off. The serial number is 28A0237039B is there anyone who can help confirm what I need?

Thanks for the help