Older bench seat in a newer truck

[86chevytrk]

Ok so I have kind of a stupid problem. My 86 truck seat was trashed so I found an older seat that was redone and installed it. My problem is the 86 seat had notches in the bench to allow the belts to come through. The older seat doesn't have this making the belts shorter. I've searched and found others with similar problems but no info on how to fix this. Anyone have this issue before? Please chime in. Any help would be truly appreciated. Thanks

[Captkaos]

The 81-up seats has slots in them and the belts were sleeved in plastic to allow them to go straight up.
The 81-down seats the belt came between the top and bottom cushion.

The is no "fix" for it other than getting the matching parts.

[zieg85]

On one truck I actually did that very thing.  The belt came up a bit short but I was able to use it after I sliced the hard plastic sleeve that helped it through the seat.  It was a snug fit for someone on the heavier side though