Hy dsmith, it looks like Jim Carter has come up with a very desirable bellhousing, one that people have been clamering for for years. This bellhousing should allow you to do what you want to do, the modification is most likely a mount for the pedal shaft has been fabricated into a newer bellhousing. There were no factory bellhousings with the pedal shaft mount and the more modern post 48 transmission attaching bolt pattern. All you should need to do is confirm that your New Process transmission bolt pattern will bolt up to a post 48 bellhousing, and of course has the same length input shaft as the post 48 SM420 4spd., hope that helps.
