You'll also need a V8 bellhousing for a 55 2nd. series or newer and the corresponding crossmember, and you'll need to convert the truck to an open driveline, which usually involves changing the rear axle or modifying the torque tube rear end to an open style driveshaft. V8 conversions on trucks prior to mid-year 1955 are not quick, simple, or inexpensive, no matter which engine is used.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!