Tubbing out 1988 LX
 

Just need to know how to do this and does anyone sell a kit?

I think your best bet is to give a reputable chassis shop a call. The biggest problem is that the factory frame rails are going to get in your way so you're talking about not only a tubbing operation, but also a switch to a four link or similiar type rear suspension.

4 link
 

Where is a good place to buy one?