These billet 7075 Aluminum plenum inserts are a Riffraff Diesel original design and are patent pending. They are made to allow you to clamp down as hard as needed with T-bolt clamps so that you don't have any boost leaks. Fix your bent and crushed stock plenums with our Inserts as well. This is a budget friendly option to buying full billet plenums. Easy install, no special tools needed.
These were designed so as to add the least restriction possible while providing more than adequate structure for clamping. The Plenum Inserts have been machined to within .164" of the OEM diameter so there will not be any measurable affect on EGT's or cfm flow.