I got a 2008 4.6L triton.
I want to put a turbo on but I don't know if the the block will handle it. Tell me what you think and if there's some other stuff i could do to it that would be better. Also do you think a cold air intake would be worth it

 

If you engine is in good condition, you need not worry about the block or anything else. Do a compression test to start. If you are even on all cylinders with standard cylinder pressure, you are good to go.

See here:

Part 1 -How to Test Engine Compression (Ford 4.6L, 5.4L)

The following article and results, especially costs, are somewhat "good luck" results, but the basics are there and it will tell you what you are in for. They use an intercooler, which they lucked out on.

592HP 4.6L 2V Motor For $2,298 - Hot Rod Magazine

Book sample and source:

Turbocharging the 4.6 and 5.4 Modular Motor

Another low budget job:

Budget Homemade 2v Turbo Build!!!!

Google "4.6 ford turbo build" for hundreds more hits.

This is a bit of an undertaking. It appears you can buy "kits", google "ford 4.6 turbo kit".