Dave - you are correct (from memory, through 1977). However, hotter thermostats were being used, making the engines more efficient; and the carburetors were calibrated leaner accordingly. Smog emission is a lot more than just a smog pump.
Not saying don't try it; but would suggest absolutely no load until you do some checking with an exhaust gas analyzer. Carburetors are cheaper than engines.
Jon.
