I built a new 3.1 v6 and omitted the efi. I put on a 550 holly and msd igni box (6al) with a mallory distrib (unilight). When in park runs great and used timming light withen specs and sounds great when in park. When I drive it and get to 30mph it feels like I have a govener set at 30 mph but i dont. Motor has no smog on it, exempt. no sensors on it. Everything is new started from bear block. This is not my first build but this is my first problem like this.