USED PICKUP

Hello, I'm from Nebraska, I just bought a 1990 Ford F-150 pickup, it had 146000 miles on it. I bought it as is. My question is, I just got the truck home, and the motor blew. Yes, blew, I had the truck for a total of 2hours. Who is responsible for the motor replacement? Me or the used car dealer? I need to know asap, all help is greatly appreciated. Thanks in advance.

Hey ...Thanks for the help.
Update...The dealer replaced the motor at their cost. Also got a warrenty on the replacement motor. Thats one auto dealer I'll be going back to!!