Thanks all, I thought the supposed tech at Milodon was wrong. He didn't sound familiar with the question. Some think I am talking about the pump cover. I am not.The pump body to engine block mating surface has a groove around tha discharge port. It came new with an o-ring in that groove already installed. The pump gasket inMilodon repair kit appears to be for stock style pumps as it would cover an o-ring if installed on the21815 style HD pump. Wouldn't make any sense to me but that's what I was told by their tech dept. He sounded very inexperienced.Moparts comes thru again. Thanks guys! Bill