chevyart,
i run a 377, also filled to the water pump holes, but i run a stock water pump with an electric drive motor gilmer belt drive. I run a thermostat, but drill 6 1/8" holes around the outside of the stat, same as a restrictor maybe 1/2" to slow down the flow of the water. I've run gas and alcohol and haven't had any problems with overheating. I do run a 16 LB cap, also only water (antifreeze is a NO NO at any NHRA or IHRA track) I'm on alcohol now so actually i have trouble getting the temp up, never turning on the pump until i'm driving back to the pits. On gas i would run the pump once i was moving it the staging lanes and the run, still never went over 210*
Those electric water pumps move a lot of water and i think your question has already been answered with the restrictor to slow down the flow. I would also put a 16" shrouded electric fan on the radiator, sucking from the inside.
Don't know who built your short blk. but i also plug all the steam holes on the blk deck for strenght.
Don't know if this will work for you but it does for me.
Zip.