Looking to add seat belts in the back for my 3 kids. What length lap belt would i need. I see a lot of 60" or 72" universal belts. I havent seen any oldsmobile belts come up when google searching. I believe i need 60" belts. My interior is teal. Also can anyone point out the factory bolt locations. Unfortunately my kids are younger and still need car seats so I dont think i can use the original looking clasp style belts.

 

At the bottom of the rear firewall , just above the floor pan ( behind the seat ) there are six "dimples " in the sheetmetal .
These mark the recommend location to drill holes for seat belt bolts .
Use a large , thick " fender washer " on the outside to prevent the bolt from pulling through the sheetmetal in a wreck .
60 inch belts will be plenty long .

 

Along with fender washer, use grade 8 bolts and nuts to attach.

 

All the seatbelt vendors sell the correct anchor plates. Use them. The large surface and rounded edges ensure that you don't pull the bolts through the sheet metal floor pan.