Year: 1968-70 Description: Smog pump relief valve Application: Mustang/Shelby All Jack’s Comments: When a reproduction was first made of the smog pump relief valve it wasn’t very accurate and you could tell from three feet away.This newest version is very accurate.This version has the correct dual platings, zinc for the base and a zinc dichromate top that flairs inward just like the originals.The blue pressure-setting plug is included and is correct for the Boss 302, 428 S/CJ & Boss 429.How do you install it? This might not be the best way but this is what I do. Slowly remove your old valve by slowly prying outward along the lip with a large screwdriver. Once you get it loose it comes out fairly easy.Then press in the new valve with a small press or by slowly tapping it in with a hard rubber mallet or whatever your comfortable with that won’t hurt the finish or plastic valve.If you take your time and don’t get it in a bind it will go in easily without much pressure. Related Pictures: More Info or Links: Pressure setting plug available separately <here> Shipping US: UPS Ground Shipping NON-US: Call or email for an exact shipping quote