I now know the 4.7 V8 has a timing belt and IS a interference engine. There are some good points to having a belt, it is more flexible and quieter. Since it is more flexible I doubt you could change it to a chain.
Look at it this way, what are the chances you will own the car at 180,000 miles, the time you need to change the belt a second time? I currently own a 92 Honda and I am in that perdicament, but I bet most people don't keep cars as long as I do.
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2001 & 2004 Toyota 4Runner SR5 4X2
Both V6 and both Natural White
"Yeah, I like white and I like 4Runners"