My $0.02 - I agree with Mike H. Keep your computer controlled stuff. Give me a carb, a mechanical fuel pump, and a simple ignition, like the HEI. got gas? yup. got spark? yup. turning over? yup. If I'm out in the middle of nowhere, I want simple spare parts (and I do carry a spare HEI pickup and coil).
My weber passes emissions fine in MA. I think one of the problems is that the 258 is so damm reliable, that it'll run in such bad condition (i.e., blowing oil out the engine from all points).
Get a new catalytic converter, and you should pass.
Good luck
Pete
88YJ, 4"susp, 33"BFGMT, 9k#winch, rear homemade swingout, reb.258, 999, 4.10, weber32/36, GMHEI.