You’ll only worsen the problem by adding rake. The original seat back configuration, slid all the way back hits the cab back already. If you rack the seat back the seat bottom will be closer to the steering wheel.
The only way to gain any room is to remove cushioning/springs, replace with more modern seats or replace the steering column/wheel with something smaller.
Hope you all don't mind me pulling this back up,,,, It is exactly the problem I have too. I am going to remove the back cushion and replace it with a plywood back, foam, and I'll sew up a cover for it. this will be very similar to my Barber chair and it is pretty comfortable.I think I can gain about 3 inches. I know I need the springs in the cushion but I am hoping I can get away with less travel in the back.
