Thanks for the input guys.
It does seem really dumb to put restrictions on making any vehicle run CLEANER than it did originally, which adding injection, and and a cat will undoubtedly do..
In the back of my mind, I know it really makes sense to pull out the BBC and put a earlier Cummins 12v diesel in there and have more twist, more mpg, be done with smog. In the early 90's it was a factory option, and I have photos of the installation so I know it works...