does anybody know of a seat belt that i could find out of another car that would work properly in my 64 with split bench seat? Right now i am using seatbelts out of an 80's gm truck. This belt does not work quite right. Always loose. Has anybody had any experiance putting 3 point seatbelts into a 64?

Three point GM style were available as early as 1970s in Chevelles and El caminos with bench seats. You will need an anchor connection for the shoulder belt at the roof line or door pillar.