My 74 F-100 has the original lap belt only design, and I want to add more modern seatbelts, but not sure which I should add and how hard of a job this is going to be. I want to put better belts in for when my son rides with me as he gets older, and just because I want something better. I know I could just go with the old style separate lap and shoulder combo like in the old days, but I would really like the best I could put in for this with a stock bench seat.