Bolt size and type for 87 k5 rear seat mounts

[Squarebody brother]

Wondering if the rear seat front mounting bolts are metric or standard thread

 

[kennyw]

They are all standard GM body bolts. I think 5/16-18.

 

[Squarebody brother]

Thanks ken , I figured it out,they where 7/16 course thread for the front brackets on rear seat. I’m using a 87 tub on my 78 frame making me question bolt hole sizes and type(sae or metric)