I now have a CAD drawing for the bracket for mounting the 2002 Nissan Sentra caliper to the tube type MGB rear axle. It will require a CAD viewer to see. The .dwg file can be converted to what ever file system is used for the cutter. Also there is a .jpg file. I have not had this part cut as I am satisfied with the original drawing. This drawing is modified to "square up" the caliper as it sits over the OD of the rotor. The top yellow line was maintained at 115MM. The lower yellow line was extended by 1/16" to 3 11/16". Have your machinist confirm those dimensions before cutting. All else remained the same. When I get time I will experiment with adapting the 1998 240SX rear caliper using the "U" shaped bracket above. That additional bracket provides the correct offset for the 240SX caliper.
The journal does not allow uploading CAD files. Just send me an e-mail or PM your e-mail to me and I'll send both a CAD and .dxf file.
The "U" shaped hand drawn image is the bracket to adapt the 240sx caliper. I do not have a CAD drawing of that part. It's easy to make out of 1/4" x 3" steel bar stock. That bracket will allow the relocation of the caliper mount holes and also provide the correct offset for the 240sx caliper. I may commission a CAD drawing when I'm satisfied with the conversion
I found a problem with the hole where the 2 yellow lines intersect. That hole is still out of place. I'm going to see if I can get it redrawn.