Adding new alternator

I would like to add a higher output alternator (80a vs 40a) to my 66 Barracuda. I don't want to bypass the ammeter circuit at this time. If I install a new alternator and install a new wire ( leave old alt. wire connected) from alternator output to Batt term. on starter relay and then leave everything else alone, is this a good way to do this. I realize the ammeter will read incorrect if I do this. I already have a Voltmeter connected.
Thanks :smile: