3inch body lift and a 300 isnt much of a problem.
The 300 is a torquey engine, it wont do much past 3500rpm besides buzz and suck gas, but they run forever and have torque from a 800RPM idle grunt untill like i said 3500rpm.
If you do decide to go with a 300, the EFI ones make more power stock, but the carbed ones have alot more modification possibitlys and potential for power.
...and not to start an argument, but a good running 300 will eaisly step on a 4.0L Jeep or 4.0L Ford all day long when things get heavy and dirty.
later,
Dustin