Probably late to the party but I built a Jeep Wrangler with a 400 SBC, rams horn center dump exhaust manifolds w/2 1/2" outlets, running 2 1/2" inch pipes into a Y, then 3" pipes in and out of a FlowMaster 50 series muffler. When I decided on the 50 series I wanted the engine rumble but not the excess noise and drone that I heard about with the 40 series. I thought the package was pretty good overall noise level and rumble wise.
