Posted by Doc Dave on Saturday, April 30, 2005 at 9:57AM :
I ran across this link on the DOdge/Plymouth car forum. This company obviously sells a lot of seat belt stuff for retrofit and has how to pages, etc.
I think Paul M's (Paul from N.Y.) advice on reinforcing the pillar on the PW is good to consider before installing a 3 point however.
http://www.julianos.com/3_point_belt_bench.html