starting the engine without a stand?

[big blue 72]

I have my 250 six cylinder on a oak pallet that i have tied it to with chains. Could I hook it up to a gas can with a gravity feed to the fuel pump and crank it over or even run it for a short period of time safely?
I do have the starter hooked up and a jump starter /inverter for power,or a battery. No tranny mounted yet.
I'm just wondering .do i need to really brace this to the wall of the garage /fence posts, etc to test start it?
I can even hook up a three row radiator to it if i should?
As you can tell, i'm a plumber, not a mechanic and all the guys who usually help me are just busy this time of year ,but i wanna see if this engine will crank/run.
Any suggestions are welcome so i dont kill myself.