i believe mate you may need a hybrid mt75 gearbox, with a different bellhousing or something, have a look at these threads mate.. should you manage it let me know how it goes and what you need cus i have been meaning to do a manual conversion on mine but don't have the balls to attempt it yet.
https://passionford.com/forum/genera...t-gearbox.html
https://passionford.com/forum/genera...sion-help.html
https://passionford.com/forum/techni...-cosworth.html