I have a '86 super cab that was a 2.3 5-speed and is now a 351W / AOD / 8.8 LS. It was first a 302 conversion and after 120k mi the 302 was tired and I shoe-horned the 351W I had laying around in it. My main clearance issues were exhaust (I had to cut up and modify 302 swap headers to fit), heater plenum clearance (cut relief in housing deeper and used early 260 low-profile valve covers), and engine oil pan front mini-sump (rear sump pan) clearance with steering linkage (used a 4x4 longer pitman arm to lower linkage away from contacting pan. The AOD required significant re-working of the driveline tunnel (as in sledge hammer) and some trans X-member mods to lower tailshaft. Of course had a custom driveline made and after tearing out the spider gears twice on the 7.5" rear I now have a 8.8 posi out of a '94 4.0 4x4.
If I was to do it again I'd just put a stroker 302 (331 or 347) in it. Stock fuel system won't likely supply enough fuel for a built 392 stroker. I will say though that my near stock 351W is a kick in the pants to drive and just punching it from a stop (no power braking needed) will instantly light up the tires :)