I was wondering if i could swap the bed off an 86 f150 long bed to an 89 f150 long bed?

 

I'm not 100% about the bed mounting bolt locations but I would say yes. The bed design from 1980-1996 is exactly the same minus some differently trimmed tail-lights and a differently skinned tailgate but even those will interchange.

 

I had an old '85 f150 & my friend put on a bed from a '96 with no issues .
good luck