Lots of options depending on the motor and usage. If is not street legal and drag car only I would recommend 14 volt system and electric pump. All of your 12 volt stuff will work on 14 volts. Run an electric pump that doesn't run off yhe crank so you can run it with the motor off. If you run a motor plate you can get those cut for big block Chevy water pumps which are cheap compared to mopar electric pumps. You might be able to do electric without a motor plate as well. I tried a restricted washer in my thermostat housing and found that it liked it better wide open.