1973 i think or 1974. i ***ume you mean voltage regulators? after 73 or 74 they were inside the alternators.
Actually I'm thinking that by '72 or '73, the integral regulator alternators had been phased in completely. But I could be wrong, it's been awhile.
72 was the last of the external regulators, but some models had the new alternator as early as 1969, including Vettes and some caddys(?)
That answered my question......my 66 buick motor needs a ext. regulator....sometimes i feel like a *****...
what is the engine in? is it in a 66 buick?you could use a 1 wire new alternator instead of the old one with external regulator