I have 2 different size belt buckles on my 72 Cutlass. I'm pretty sure the larger one is for the driver & passenger and the small one for the center passenger.
However, the clips on the retractable belts are the smaller size. Did someone buy the wrong ones? Not sure if I should buy belts with smaller buckles or retractables with bigger clips.

 

The small buckles are typically front seat (buckets for sure, outboard bench maybe?) and use retractors on the male side. The larger buckles are for non-retractable positions such as the rear seat.

 

sorry, I didn't mention it's a bench.

I only have one small, 2 large

 

I do not know all of the belt combinations, just the ones for bucket seats. On those, starting in 1972(?) the outboard male retractable belt has a keyhole slot for the shoulder belt to clip into.

I found this picture on the web showing a 1972 with bench seat and Deluxe belts. Note the small buckles and outboard retractors, and the keyhole slot in the male tab.

The tag sewn onto the belt near the mounting bolt end will have the belt model number and year, so you can check to see if those are even the right year range for your car.

https://www.fastlanecars.com/vehicle...utlass-supreme

 

Wow, I remember that key hole now that I see it from the 72 I had as a teenager.. I found the other small belt in the pile of seats. There's no key hole for the shoulder strap.
The shoulder straps have the big male tabs, maybe they fit into the big buckles? Definitely not the original setup.

Is the big 71 the year?

 

42 is the week, E is the style (deluxe, standard,etc), and 71 is the year.
42 = October
E = Black Deluxe (I think)
71 = 1971
By October of 71 GM would have been making cars for the 72 model year.

 

cool, thanks

 

My 1970 had small buckles for the lap belt and large buckes for the shoulder belts. I think it was 1972 when the keyhole slot was incorporated into the lap belt (I edited my post above).