Call and talk to gus, Ohio Generator has OUTSTANDING customer service, they never mind your phone call and they explain everything you want to know in great detail. Plus there alternators come with a birthsheet and they are tested to prove total output before you recieve them. I do not know about any of the other companies, I heard good about Iraggi, but I heard a lot of bad about him too. The big thing is you get what you pay for like everyone else says.
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This is my alternator there is pictures and all take a look and read through. Hope this helps