F-150 suspension swap
 

Ok, I want to put the engine and 4wd drivetrain from a 1978 bronco under a 1973 F-150 or 100. Or maybe even the front axle and transfer case into a 73 F-250.
What I reallywant to know if any of you out there knows if the 1973 1/2 ton frame is the same as the 1978 1/2 ton frame.And if it is not the same what is the differance.
Thanks for any help you all can give me!
Jim T