I bought a 1991 D150 that originally had a V6. Previous owner put a 1989 318 in but made their own mounts, one of which is using a lug nut and a chain wrapped around the frame...

Anyway, there is a 1987 Ramcharger at a junk yard with a 360. I know the crossmember changed around the late 1980s for the V6 trucks. Are the 360 and 318 engine brackets the same from the 1987 to 1991 frames? I know the mounts are the same but I need the correct bracket that moves the v8 engine mount further forward on the frame. Ive been searching forums and looking for pictures. Coming up empty handed.

As of right now the engine is not level from side to side. Passenger side is about 1/2" to 3/4" lower than the driverside.

 

that looks about right, Id bet the rubber is just broke on that mount. Jack up that side of engine (flood jack and 2x4) and there are 2. 1/2" nuts (take a 3/4" wrench or socket) one on top, the other below that "biscuit".
the "biscuit" is what you'd need to replace, they aren't expensive. for what they cost, I would just go with new vs junkyard. maybe just take out the bottom 3/4" nut (with engine supported from bottom) and take teh 3 bolts that hold the "U" shaped deal to the block, and take that with the biscuit out, may make it easier to get at the top nut (in the bottom of the "U")
and so you know, the driver side frame bracket (The "U" shaped thing) is different for 318 vs 360. but the "biscuit" part would be the same between them. and if I remember right (its been a while since I messed with one of these trucks) 2wd vs 4wd won't matter for the "U" shaped bracket or the biscuit. They used that same biscuit mount from at least 1972 on. also used on A body (Dart, Valiant) til 1972 before they came out with the "spool mount" for '73 on those cars. but the bracket that bolted between the biscuit and the engine was different on those.
wow did they butcher the pass side. Id bet there is a hole in the crossmember or at least a dimple for a hole under the U shaped bracket on the pass side. that is weird because the V8 is LONGER than the v6 was... by the driver side it looks like the engine is sitting in the right place. Its been forever, since I have seen a 88-93 with a v6.... 87-older with the 6 banger, had an INLINE 6 in them.
the V8 bolts up to the V6 trans (with trans in same location) The inline 6 of older years wont bolt up to a v6/v8 trans. If manual(stick), there would have been a different bellhousing.
the auto trans would sit in same location regardless of original engine.

When the motor mounts break, the rotational force of the engine makes the driver side of the engine "lift" when the gas pedal is mashed.... that chain as a temp repair was super common on many brands of vehicles back when vehicles were predominantly rear drive.