So I just cracked the heads on my 97 4runner. It is the sr5 with a 3.4 l motor. I have a 4 runner with a 3.0 that is not blown. Can I swap out the 3.4 with the 3.0?

 

The 3VZ and 5VZ heads are different. They have different passageways for cooling.

 

Is it a 3vz-E, I think you will find a lot of incompatibilities like sensors, wires, cluster, Obd2 and ECU making it a lot harder than finding another 5vz-Fe that will drop right back in. You would have to have driven it without rad fluid to blow both heads usually, and at that point it would be wise to try another motor incase other damage has occurred.