8 When it comes to sending fuel to the engine, the original block-mounted mechanical pump must be replaced with a high-pressure electric unit. (Don’t forget the block-off plate for the stocker.) Slebodnik used an external pump and filter for a late-’80s/early-’90s Ford F-250 with a TBI 7.5L (460) engine. The GM TBI runs with about 12-15 psi and features an internal pressure regulator. But even with this electric pump, it still needs gravity feed, so the pump must be mounted below the tank. The wiring must also be run to a relay under the hood, so be sure to keep it away from the exhaust.