i was planning on takin the back seat out of my 87 and putting it behind the back seats of my 89 if you have any tips or input let me know

 

take some measurements. you will find that it won't fit due to the wheel wells and Roll bar.

Seat belt Plans?

 

If you need third row seating, get a bigger vehicle. Those trucks are too small to carry that many people.

Besides that, as OC pointed it, the roll bar and wheel wells will get in the way.

You also need to think about how you will get someone into the back seats. You would have to endure the hassle of folding the "middle" seats down, which means squeezing into the back, unlatching the seats, then squeezing people into the 3rd row.

Can it be done? Yup. Is it practical? Not at all

 

Make it face backwards and get in through the back. Find a small seat. Possibly from a cj? Mount the seatbelts to the roll bar and beef up your springs.