'69-'70 Corvette alternators

[Leonard M.]

There's been discussion on the hard to find, expensive 69-70 SI alternators. These have the open face front case with the "ribbed" back; with and without raised rectangle below DELCO.
I agree with the reply Edward Cervo made in the '69 Alternator Clarification Post.
I think that the open face front case on the fakes are service replacement parts that were stamped recently and are not factory parts. I do not think the ribbed back have been remanufactered and those out there are original.
Like Edward said, lookout for the Nice casting which has the sharp straight edges with the square bottom corner.
The pictures are to show the clear cut differences.
The first picture I show is a "new" unstamped open face front case.
The second is the same type of case with a Recent stamp; 100% Fake.
All others are what I believe to be genuine factory alternators.
I'm guessing the fake will pass judging, but if someone is to pay $1000. I would rather have a "real" one with a weak stamp or a case with a wrench scar.
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[Sal C.]

Re: '69-'70 Corvette alternators

Just look for the Delco logo

[Edward C.]

Re: '69-'70 Corvette alternators

Just look for the Delco logo

There is a Delco logo on the front case? I never noticed it. I’ll have to check that out.

Leonard,
I don’t think the smooth front cases are even service replacements. I think someone just recast them. I can guess from my own experience with casting parts that the originals that have the rough flash were made with a two piece mold that was cut right down were you see the rough flashing. I am guessing whoever cast the “newer” cases decided to make the molds come apart in a different spot. Depending on what method they used to make there molds the rough edges could make the removal process more difficult, maybe. The smoother the piece, the easier to cast. Either way, it’s an easy way to tell. They did make service replacement front covers that are original and have the flashing. When those are restamped it’s very hard to tell. In fact, I’m not sure I would be able to tell. Some of the restamped front cases are done very nicely and I can only be sure because of the smooth front cover.

I don’t think the rear cases have been redone but if they did them it might be hard to tell if it’s a direct copy.

Also, these redone cases have been around for awhile. Many years. I’m sure this has been covered, but maybe not for some time. And with prices starting to climb on original parts, maybe it’s worth noting again.