It should bolt right up to a 258(4.2L), it uses the same bolt pattern as a AMC V8. The 4.0 FI engine is a Chrysler designed engine, it has a fancy sensor that gets in the way when bolting an AMC bellhousing to it. You could machine away enough of the belhousing to make it work, but I couldn't tell you how much or where to take the metal off from.
The Jeep TF727 should have the NP style x-fer bolt pattern, so yes your D300 should fit nicely. That is if the output and input shafts matchup corectly. Look it up in the Advance Adaptors manual. By the way, many of the the AA manuals are now offered free (including the Atlas manual, but not the NV4500, at least yet) in Adobe Acrobat format(*.pdf). Check out their website for more details. Adobe Acrobat is free to down load as well.
(thanks to Sycho 15 for the help in html, and I am still learing)
I think what they were saying is that the minium clearance requried for the TF727 clearance issues is a 2" spring lift. But might not make it one every vehicle. A better fit would be 4", then you should have no problems.
llll '90 YJ, NV4500, XD9000i, 35" MT/R, Snorkle, 4.5" RE lift, Tera Revolvers, etc. etc.