this $hit is easy i better get the ten points.
4th Generation 4runners (2003-2009)
if its the V8 like you stated then its the 2UZ-FE motor (4.7 V8)
the 2UZ-FE uses a timing belt (4.7 V8)
if its the 1GR-FE then its a timing chain. (4.0 V6)
i do believe it should be replaced at 100k miles (timing belt).
(Just FYI i am doing the same with a honda civic and the dealer recommended interval is 105,000.)
en.wikipedia.org