1759VBP GEN I SBC with Vortec Bypass PortMore Power. More Heat! Flowkooler pump 1759VBP is designed for Gen I SBCs with Vortec heads. Unlike internal bypass passages found in older blocks the Vortec blocks and heads do not have the internal bypass passages so the the coolant bypass is an external hose connection from the water pump to the intake manifold. You run a bypass hose from a bung on the top rear of the water pump to a matching threaded port on the intake manifold to ensure