At one time I thought they were supplied by A&I but I'm not sure.
 

OM I am not positive, but I swear some of mine came from AIM aka American International Manufacturing in Woodland, CA.
I have always wanted to take one and compare to a pump adapter for a small engine/wood splitter.JM

You might check with C C Battery in Corpus Christi, Texas. Many years ago they sold a similar conversion.

You may want to try these guys.
 

Thanks for the responses but I was hoping someone had first hand knowledge of who builds the units in the picture.
I'm fairly well familiar with who sells them but hesitate to ask who the supplier is.
Juiceman, AIM has a familiar ring as a source, at least the early versions that used the Motorola alternator. Do you know anyone associated with AIM that might know if they are still a source?

OM: I have always wondered myself of the actual manufacturers of the adapters, being the high cost of them;the one wire alternator is less money! That is why I would like to take one and make a comparison with the adapters for a gas powered wood splitter unit. I see them in catalogs and they are not near what these alternator adapters sell for.
There used to be a farmer that had his own foundry here, reproducing ag parts for resale. Its too bad he isn't around anymore.
I will ask my favorite wrench man. Sorry, I do not know anyone there, but will try to have one of my vendors that use them inquire. JM

I just checked with a friend of mine that is one of the owners at AIM. He said he could look and see if they still had the drawings for the adapters. He said that it has been 20+ years since they made any. Hope that helps.
Mike B

Thanks all for the responses, that's the sort of insight I was looking for.
Juiceman, they are more than just a pump type adapter. There is a center support bearing in that housing. Still it does not seem to justify the current prices.

OM: I can ask if AIM would make any more if there was a need for them. Let me know what you need and I can ask and see if I could get an estimate on price.
Mike

Thanks for the offer. Before doing that I would still like to know who is currently producing these as they are available. Just don't know the current  manufacturing source.