The Stovebolt Site Forums The Shop Area The Electrical Bay Alternator question sort of

For the 350 motor in 1970, alternators were on both sides depending on if a smog pump was required. That depended on size of truck, which 350, which transmission, model of truck, California or not. If no smog pump (A.I.R.), alternator was on the passenger side using bracket shown. If it had a pump, alternator was on drivers side. The confusion is due to folks taking off the pump themselves and moving alternator to pass side. Adding to the confusion is owners swapping other year 350's into a 1970 truck.
It will look more normal, more Chevy, cleaner, if you mount it on the pass side with the bracket shown.

Can't say what MVD inspection will say about what your truck should or should not have. If their books say smog pump, and it's missing, you could fail emissions test.
Some states are getting more fair about it. More realistic. They have done studies that show, for instance/for example that the amount of 1970's still on the road contribute less than .0001% to pollution, so why get jiggy with inspections of them. We don't inspect 1966 and older here.