Plus the 4.0 is one of Toyota's most reliable engines made..
On par with the 22R engine for reliability?
We have a couple Toyota trucks, and our neighbors all run Toyotas, plus one of our neighbors is a mechanic familiar with Toyotas.
First, the 92 had the 3.0, which might have been Toyotas worst truck motor (in the US anyway). Even then, it went 199,000 miles before it blew up. It got replaced with a 3.4, which has a reputation for more power and far better reliability. It runs great and should be a great motor upgrade.
The 2009 has the 4.0 with 167,000 miles and it is a bullet proof engine so far. It has more power but I can't stand the automatic transmission they stuck behind it. The truck sounds like it's vomiting when you accelerate. But it does accelerate. LOL I've heard the 4.0's are not rebuildable but I haven't researched that claim. Seems dubious to me.
The new 3.5 does ok in my friends truck. Not a powerhouse but not a dog.