[chemnick]

Greetings:

I have switched to a Vintage Air Gen IV AC system on my 67 GTO. I had replaced the engine wiring harness during the restoration a couple years back. It is AC, RA, points distributor, external regulator type (will be available soon). Since the new AC setup doesn't require an AC harness and I'm changing to an HEI, I'm getting a new engine harness again. The question is, is there really any operating advantage to running an internal regulator type alternator? I have no issues with the external type, but I might be going to a higher output alternator later on and if that is an issue I want to do it all at once. I know I can get a high output unit in the external type and wonder if there are any regulator considerations for them. I am running a solid state external regulator now without problems. I do not know if the harnesses for internal type alternators still leave the battery light functional either. Unless there are reasons not to, I intend to get an M & H harness. Thanks!

Chemnick

[chemnick]

Thanks for that input, man/mech..............................

[Schurkey]

The 10DN (early style) alternator replaced the old generators because they were both "smaller 'n' lighter", and they had much greater output at idle.

The 10- and 12SI (first-gen internal-regulated) alternators replaced the DN series because they put out much more output at idle.

The CS replaced the SI because they had greater output at idle.

See a pattern? It's not that the old alternator can't be made to throw significant amperage, but it can't throw that amperage at low rpm. Of course, each newer generation of alternator has greater peak amperage ratings, too.

Scrap that 10DN for at least a 10- or 12-SI. The SI series may be the sweet spot when comparing output, reliability, cost, and serviceability even if they're a generation or two (or three) obsolete.