This is just my opinion, but I'm pretty sure that before it did any damage to the engine, it would most likely blow the exhaust apart at a seem or a seal. Also I would mount it as close to the engine as possible like the other guy said, that way it doesnt have to build up pressure in that large of an area.
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2007 Bighorn 5.9, 5" from downpipe to 5" stacks, Edge EZ, BD boost fooler "Why don't ya ask my be-hind! That is if ya can catch it! Whata ya say ta that HYDRO PANTS!!!!"