[metroschultz]

Having been in the biz since the '70's (when rock was new technology), I can tell you that air injection of that era was in-efficient at best.
We (me and all the other wrenches I knew) would joke that the AIR system was just watering down the dirty exhaust with fresh air. (think big glass with 2oz milk,,then pour in 14oz water). the gist of the joke was; The EPA was too stupid to realize the car companies hadn't "fixed" anything, just diluted it so total volume would seem cleaner. You take 'dirty ' exhaust at the manifold, inject clean air from the front of the vehicle, you get diluted exhaust out the tailpipe, (where emissions are read). Duh.
We all understand that by adding fresh air to the exhaust stream you may, possibly, perhaps, if the conditions are perfect re-burn some of the loose hydrocarbons. Real world experience tells me thats a bunch of Krap.
Make a cleaner engine in the first place and the rest falls into line.

I say Yes, go your route, I would even get the emissions tested after mods to see where you stand. The Reg's back then were fairly lenient, and I am of the belief that they can't force you to make a 1979 auto meet 2008 Reg's.

If ya gotta getta cat then so be it. There's plenty of high flow cats out there.
Drive safe. S.