You should spend a good amount of time reading from certain websites. Here you can learn all you need to about the swapping parts, anything outside of the longblock.
With the crate engines, much of what you think you are saving will be lost because you should not use anything outside of the longblock, plus the camshaft. The cost of those parts, plus having them and needing to sell them, it makes any non Explorer crate engine a waste of money and time.
Those high HP #'s you see with most crate engines will be at rpm's higher than you need, or should reach. My engine will make more power at any rpm than those, up to about 5000rpm. To use that kind of engine that is down on power until right when you need to shift, I call that a poor engine for the vehicle.
The main concern that a swap project should have should be the functioning of all of the parts which were not original. Meaning that if you have a V6 now, you should first worry about getting a V8(of any quality/size) to run, plus the trans, TC, air cleaner, MAF, exhaust etc. You should look at the internal engine parts as a separate project.
You can do a swap and achieve a total bare bones cost of well under $1000. If you do it right and get that done, then you will have a confidence to set a new budget and get the work done. By then you will be able to know what you could invest into a long block. Regards,