I instald one due to 10 in of vac on new motor and cam. 236/242 @.05 112 lsa and 396 SB. I was told I need a check valve installed. Pump is in and works s well. pulls 16-20. How is valve plumbed in. Right now pump is pulling only brake boost. safety issues in future that way.

Thanks

Ronny

 

The factory booster has a check valve as the Inlet fitting. That's the only one you need. Maybe I'm not understanding you correctly? Your post is a little hard to read