Jack stands are a must when placing your self between the truck and the floor. I have jacked up the truck however via the center of the front axle without issue in the past. Not something I could recommend though.
1950 Chevy 3100 Blog w/Pics -
http://txchevy50.blogspot.com/Goal: Clean, Rebuild, Paint, & Drive on a budget. Major restore of components will be done over time.