I have a 496 bbc 13.5. Ompression motor. I have a sullens dominator on it. It ran well at the house. Took it out for a drive it ran well but every now and then when driving at about 3000 rpm it would stumble when coming to a stop. Today I got more fuel checked it right at e85. Ran great til the first time I stabbed it then again bad idling where I could barely keep it running. Let cool down. It idled barely. I've checked floats. Fresh -7 plugs. Hvc coil msd 7al2 box. Prostar 500 pump. This is driving me crazy.