My machinist told me they are all the same except gaskets and fancy paint unless they are reverse rotation. He doesn't stand to make a profit off the inflated margins at a marina, I think I'll believe him. I'll use the marine cam, so it should be good. The guy dropped the price and is including a bunch of ebay fodder, It's cheap enough I'm going to do the trial and error method to see if it will work. If it doesn't, I have a good core, since that's about where it's priced at.