what kind of fitting for the fuel valve on the fuel rail? I wana see my FP while idling.

 

Are you wanting to remove the shrader valve and use an aftermarket fuel pressure guage? Or do you just want to hook a guage up to it for testing purposes?

I used a fuel pressure guage I got from my local auto parts store. It screws right on to the shrader valve on the fuel rail. If I want to test drive I tape it to the wind shield so I can read it while driving.

I do know however that the tread on the shrader valve into the fuel rail is 5/16 x 18...

 

You can pull the valve core out and connect a -4AN fitting line to it.