Some, 86's and 87-90 4.2 have a different valve cover. It's the same as a 4.0. I have several of those but they won't fit your 83. unless you have a latter cyl head.
86 CJ7 5.7 vortec. 4L60,D44's,OBA,Air tank bumpers w/D rings detroits,4.88,35" bfg, mt's 9500ti warn
86 CJ7 2.5 detroits, OBA 4.56, air tank bumpers, w/D rings,9500I warn 31x10.5x15, Trxus
86 CJ7 bone stock, w/factory 44 never seen the dirt soon to be for sale
87 Wrangler also never seen the dirt.