If you want some pics and info from someone who did this swap a few days ago.....here you go. I cut and past from another thread, but you'll get the idea...
Also pulled out a body. 87 YJ tub with very little to no rust. Just surface in a spot or two.
Here's my buddy Brian sanding off the factory decals from the sides. He's been a big help! That his bad a s s white TJ in the background.
It really looks way worse than it is. Its very dirty from storage. Those are leaves that blew in under the cover and settled on the floor.
Last two days was turning a YJ tub into a CJ tub. First the decals had to go and when they are that old, you almost have to take it down to the metal. Next was addressing the defrost. I cut out out the CJ section from wrecked CJs and weld them in. I pick a common point like a bolt hole and draw the same line on each tub section, Then cut on the line on one and over the line on the other. It makes for a nice fit and easy weld in.
Since I'm running a CJ windshield, the holddown plates in each dash corner would be off by a little over .5 inches as the YJ moved them outward. The sheetmetal stamping still reveals the space in the movement. I puched out the nut and elongated the hole. The upper corner dash bolt was off two, so both of them went on a nut plate that was tach welded in the center. All the other holes matched up just fine.
Then the rear of the tub needed some mod work. The swing down tailgate fits fine, but needs the hinge holes at the bottom. What I do is cut an oval in the back of each hinge area and use a plate with welded nuts to go inside the rear channel. These were cut when the tub was upsidedown to gain easy access.
The gas filler is traced out using an old paper bag and transfered to the right side. The hole is the actual size, so if you cut just on the outside of the line, it will fit back onto the other side IF you want to fill it back in. I'm going for full CJ here so it was moved and fit fine. A very thin coat of surface filler was all that was needed after the weld was ground down.
The two body mounts on the rear crossmember are off by .75 inches between the CJ and YJ as the YJ went to a wider frame. I usally relocated the frame holes, but this frame was already galvanized and I didn't want to mess that up, so I drilled the new holes and tapped the floating nut inside the tub.
After the tub was sanded, cleaned, and sanded some more, the paint went on. It was at night, so the colors are off, but you'll get the idea. The swing gate holes were drilled and the outer YJ ones were welded up with small square patches. (I still have to mount the cable tabs in the tub and drill the left side)
Even filled the double washer sprayer for the CJ single one.
Heres how the tailgate turned out. The CJ brackets were welded in.
The one thing I didn't do on this one was weld in the two heat shields. One goes on the fire wall lower left and another under the rear floor.
Also not shown is the oval hole cut for the clutch linkage rod. Other issues are the fender supports and studs/threaded holes for those. Measurements off a good CJ tub are a must.
