Is it true that on a 1980 Corvette that you havee to rev the engine above 2300 rpm once to get the altenator to start charging?

No that is not true. Once the belt on the front of the engine that is connected to your alternator is turning, the armature in the alternator is turning, it is producing electricity. The faster it turns the more amps, (power) it puts out. There is no electrical circuit connected to any normally produced automobile that requires a set speed of the alternator to activate any electrical products. If you have an alternator gauge, you will notice the faster the engine revs, the more output the alternator puts out up to a set point. there as far as I know, no need to rev your engine above 2000 rpms to activate anything. If the friend or confidant disagrees, find out why he is saying this, and let us know here.