The Aeroflow Performance GMLS water cross-over kit provides a clean, professionallook while providing proper air bleeding for the cooling system and can be used with ftermarket Carb or EFI intakeswithout modifications. Will Not fit factory intake manifold will require use of 10mm spacers. This Stainless Steel Steam Vent System connects the 4 corners of yourLS engine to remove trapped steam and get it where it needs to go. When steam gets trapped pressures rise, when pressures rise it creates an unsafe tune condition which can lead to pre-detonation, head gasket failures, lean cylinders causing engine failure. This setup combines our compact distribution blockand swivel cross over adapterswith 1/4" 304 stainless steel line. Requires only 20mm(25/32") of intake manifold clearance.