Techniacally the government has made a lot of pre 86 cars illeagle to drive on the road.
One of the main reasons is that they belive lead in the air is bad ( they got that right)
so they came up with unleaded fuel. now most post 86 cars are set up for unleaded with all the pollution gear cats etc but there was never anything that I can remember stating that we had to upgrade the polution gear in the pre 86 cars.
most of you who are running with out a cat are pumping benzine into the air this is more harmfull than lead in the air far worse for the environment.

one thing I would recomened is fitting a cat hi flo of corse any cat should fit in somewhere along the line. then do what people do with gas conversions and fit the upper valve stuff. this works the same as squeezing the little bottles into the fuel but its easier as you dont have to measure each time you fill up.

also get a tune to suit your regular fuel octaine if you run premium then tune it to 95 - 98 octaine if you run std unleaded tune it to about 92 octain fuel. your mechanic willl tune it (if he is any good)
my 2c