Stacks...
I think you can add reduces onto the bottom of the stacks to make it work. I know that the bigger grand rock stacks go down to 5" but like I said a reducer should work, but don't quote me on that
the biggest thing you would have to worry about with rain is if it did rain enough in theory it could get all the way up to the turbo and hydro lock the engine...but were talkin and ungodly amount of rain...the biggest thing that will happen is the flex pipe will start to rust out after a few years of rain getting down in there...like mine

If it rained enough to fill your exhaust system back to the turbo, I think the truck would be under water and the least of your worries
7 aussie ceramic coated matte black---AutoMerged DoublePost---


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Last edited by 07dmaxclassic; Mar 14, 2012 at 09:58 AM. Reason: Automerged Doublepost
+1
drill a small hole at the lowest point. the exhaust will rust faster from the inside out.. otherwise when you start it after a heavy rain it will throw soot filled nasty water 10' up in the air which will rain back down on your truck or whatevers nearby and make it nasty.
drill a small hole at the lowest point. the exhaust will rust faster from the inside out.. otherwise when you start it after a heavy rain it will throw soot filled nasty water 10' up in the air which will rain back down on your truck or whatevers nearby and make it nasty.




and so far i've havent had a problem.