I've just replaced the seat belts on my 1972 4/4 with internal reel units.
The unit you need is a 90/90 angle unit - I got mine from Quickfit Safety Belt Services but not sure they export to the US.
The MSA require stage rally cars to carry a seatbelt cutter/life hammer for both driver and co-driver and fitted within easy reach of driver and navigator.
Arwyn
