How much HP should I expect to gain on a stock 5.8EFI

 

What is a Motorcraft Supercharger?

 

If it's the same one that's in the Ford Racing catalog, then it's a Powerdyne centrifigual. I think they are set to produce 6psi, but you can pulley them down to make 8psi, though I don't think the bearings are very reliable past that. With a supporting fuel system and a good tune, 100hp (or slightly more) to the rear wheels is possible.

 

It is manufactured by Powerdyne. Thanks for the input.