A 86 bed will go on a 92 frame, but you need to cut 2 sheet metal brackets off the 2 middle under bed supports. The 92 frame has 2 little bulges that account for these. The year cut-off is sometime in 1989- we had a epic thread on moparts from 2011 about this but I can't find it now. But heres pics showing the gap (one of 2 on each side) from running a 90 bed on a 88 truck. You have the opposite problem and need a date with a sawzall

see reply 96, 6th and 7th pics down for pics
http://ramchargercentral.com/mopar-trucks/1988-w-100/50/

Last edited by jerseybud; 02/26/18 01:34 AM.