Damn, I'm looking at the pictures of the fuel reg.

I just checked the stock rail, that little O ring is still down in there, and was not transfered to the new regulator body.

I have the SC fuel rail and reg off the engine and apart now, the new reg body doesn't have a recess for that little O ring like the original one did. Should I just stretch over the bottom nipple on the regulator insert?

Obviously this seals the return line, and is what(should) hold pressure in the rail.

John C.