[b454rat]

I did the same thing to my 89 crew cab. Was a2wd dually now a 4wd SRW. Like you found out already, a 4wd engine crossmember doesn't fit. I had one from a 1/2 and a 1 ton, both are the same, of course neither fit.

I used DIY4X B-52 kit to mount the front springs. If you call him, he can make them for standard width bushings, but are made 3" wide. I used stock length 48" springs, just cut the bushing down 1/2" overall.

As for the engine crossmember and mounts, I used the 2wd engine mounts and boxed them in similar to what 4wd mounts look like. Then just get a piece of DOM or tubing to make a crossmember to tie the frame together.

I think I still have the link in my sig, there is some pics of my crew in there that shows the mounts.