T-4 Stainless Diesel Cummins Exhaust Manifold. 24v Sled Puller Stainless Diesel exhaust manifolds come with 2 ports drilled and tapped for EGT & Drive. Our Stainless Exhaust mainfolds are made with shell molding. Its a super smooth inside and out casting technology that has superior flow over and above the old type 60 grit sand paper looking and filling casting that all the other exhaust manifolds are made from. The manifolds have 3/4 inch thick center section [for those of you that like to custom port to your specs]. Thick wall casting to keep heat in. The inside runner sizing is 1.650 inchs all the way to the center outlet for high flow. The stainless manifolds make large turbos more drive-able, improves spool-up several hundred rpm's. Improves horsepower and widens powerband. Increased economy, when installed with same mods. Excellent fit & finish! Has superior flow over the competors. Has large 1.65" ports, full length to collector foot. Smooth runners with extra porting room.