My converter builder ran one of the super stock classes...not sure which one. His car had a 304" sb chevy w/ bowtie aluminum heads (nothing real exotic, had to have a factory part number), a sheetmetal manifold, and a pair of little holley 600 cfm carbs I believe. That engine made right at 1k hp and turned 11k rpm at the stripe. Impressive stuff. He was laughing about the converter and it being a 7" unit that flashed to around 8k rpm if I recall correctly. This was probably 10 years ago.