IMO trash the emissions setup. Those systems do almost nothing nowadays being as old as they are. By getting rid of the emissions, the motor is not weighed down on the front end and actually performs better. Having an emissions system from that time also opens the possibility of exhaust leaks all over the place because of the tubes that run from the manifold to the smog pump. Now I'm basing most of this arguement on the 305 that I removed from my malibu years ago, but trashing the smog system was the first thing on my list. Did the same thing for a friend that has an 84' silverado pickup that has a 350. Cars from the 80's and back are not penalized as bad because they're expected to not have "great emissions". Now this strongly depends on where you live too. In the south, cars are a way of life and we live by that. In the new england states and much of the north, there are strict laws against cruising and any aftermarket or older vehicles. I remember being in maine and being told that they were going to write me a ticket for making more than 2 passes along the beach within an hour in my 80 malibu. A day later, I had 6 squad cars pull me over for no viable reason, just to say that the color of the car did not match my insurance.
