I used to use a spare sub-frame for testing engines. I have seen them run on a stand and they say it is safe because the recoil doesn't react with the block. I am not sure about that. Maybe chain it down to be extra safe? The 455 in my car right now is hooked up with the HEI and just the 12 volt 'pink' wire going to an ON/OFF toggle switch and then right to the battery. The battery is hooked to the starter and grounded to the block. A wire is hooked from the + battery post to a momentary push button on the dash and then to the 'S' terminal on the starter. It is all the engine needs to run. I run a fuel line from an outboard motor portable 6 gallon tank to the fuel pump. I did slip-fit a short fan belt over the crank pulley and the water pump pulley. I have a radiator and hoses in place with the heater hoses tied together. I can run it a short while without overheating. You know as our waters are getting warmer we are seeing Southern species more often. My daughter caught a 42 lb Cobia a couple of years ago. Hey, it takes some tough fish to swim around NYC. Like this guy:
