Gear Vendor OD Blues RE: 73 Duster
The next step beyond that is a re-geared, properly built 4L60 with all the goodies in it. Which requires the same crossmember trimming and a different transmission mount.
The 2004R, properly built, is an amazing transmission and one of my all-time favorites to drive, but I do prefer to use the Reid SFI Bellhousing to mount it. Fitting this trans does require trimming the torsion bar crossmember and a modified rear transmission mount. No floor cutting though.
The next step beyond that is a re-geared, properly built 4L60 with all the goodies in it. Which requires the same crossmember trimming and a different transmission mount.