First of all you can fail a smog check with any induction system if it's not operating properly. Fuel injection is not a cure all to pass emission testing. I personally have had to get a car through Tennessee emissions that took me 3 attempts with a carbed car with a catalytic convertor. I also know people that have failed emissions with fuel injection.
The beginning of this post was about substituting LS engines for Stratostreak engines, not what type of induction system are on said engines because you can buy an intake to run a carb on an LS engine as well as buy an aftermarket fuel injection setup to retrofit on to a Stratosteak engine. Doing an engine swap of an engine to pass non existent emission requirement is an excuse, not a reason.
If they ban pre 1985 cars off of the roads your still not going to be able to drive an LS equipped 1970 car........................
I have not one thing against fuel injected ECM managed cars, my concern is just because the engine came in a car equipped with tight emission controls does not mean it's the be all, end all, of powerplants, and I own one. I have an LS2 in my 2005 GTO, would I put one in my 1973 T/A, nope. There is absolutely nothing wrong with an LS engine, there is also nothing wrong with a 455 in my Q Jet equipped 73 T/A.