GM LS Flow test starter kit. This kit allows flow bench technician test LS2/LS3 Cylinder heads on there flowbench. Bore stand has a 5 inch square bolt pattern and fits Superflow style flowbench and others. Cylinder head mounting to stand is done by large c-clamps or purchasing a conversion kit for slider plates. These kits are a made to order process time 7-10 business days . Items included. Acrylic bore stand 4.030″/4.155″ +- .010″I.D. Tolerance. Base sealing rubber gasket/ EL series Valve opening fixture with case/ LS-2 inlet flow guide (IFG)/ LS-3 inlet flow guide (IFG) LS-2 pedestal adapter/ LS-3 pedestal adapter.