I have a sbf that was originally a smogger. Took all that stuff off and replaced the carb with a Holley 650. Runs way better now, however when it is fully warmed up something weird happens. When I shut if off and restart within a couple of minutes it revs very high and I can go down the road about 35-40 mph without touching the gas pedal. After about five minutes of driving it settles back down. It kind of feels like the choke has reactivated or something. Any ideas?