Can big end rod bearings be replaced without pulling engine?

 

No.

 

Oh, I was told I could unbolt engine mounts and jack engine up enough to get pan out and then do them and the crank bearings? I have access to a 4 post lift to do it.

 

You can do it like that but the firewall will not allow you to remove the pan.You will need to pull the engine forward just enough to clear the firewall then you can drop the pan.But,if you're going to do all that the final step is to just pull the engine from the truck.