FAST LSXRT intake manifolds are designed specifically for GM cathedral port truck engines (4.8L, 5.3L, and 6.0L) and cathedral port LS1, LS2, and LS6 race applications where hood clearance is not a concern. FAST LSXRT 102mm intake manifolds follow the path chartered by the original FAST LSX Gen III intakes by featuring a modular design that allows for easy porting and disassembly and a runner design that yields an incredible 25 peak horsepower gain over the stock intake (on a stock 6.0L engine with a Big Mouth 102mm throttle body). Similar to the LSXR 102mm intake manifold for cars, the LSXRT features the ability to remove individual runners for modification. LSXRT's are constructed from a proprietary precision injection molded polymer which offers many benefits, including lighter weight, greater strength and lower heat soak propensity. While they feature a 102mm air inlet that was designed for the FAST Big Mouth 102mm throttle body, they can also be used with stock 90mm or aftermarket 92mm throttle bodies (78mm three-bolt throttle bodies require an adapter). Other features include integrated nitrous bungs and precise bolt-on fit that permits the use of factory accessories and OEM fuel/emission connections without adjustments or clearance issues. Some GM truck models may require the FAST 92mm or 102mm throttle body.