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Sorry about the confusion! I wanted to know about the disposition and construction of the timing belts or chains on Subaru’s two main engine's, 2500 and 3000cc, I believe. Do they use chains or belts and are they internally fitted or accessed under bolted covers. 
Thank you for your help!

Subaru went to timing chains for the 4-cylinder 2.5 around 2012-2013, depending on model. At that time the 2.5's head gasket issues were also finally resolved.

The six-cylinder 3.0 and 3.6 engines always used timing chains.

(Information is from the rockauto.com database.)