Not answering the original question but rather following the thread... I started with D&Ds. Didn't like the look. Sold them and bought stock America pipes with the first two baffles drilled with three 1/4 holes. The performance loss was blatant. I did Poppy's method but with a long "T" post. My experience was much different. The chisel part must make a lot of difference. Anyway- I beat out the first two and there was little change if any, so I beat out all of the baffles. It was still quiet enough to sneak out of the neighborhood in the morning, but had a good thump when getting on it. The tone of the exhaust was perfect. It was deep and had a presence. I got lots of complements on the sound- even from Harley owners. But the performance was not that of the D&D's. Being an idiot, I opened the exhaust all the way. I took out the chokes at the coupling and the big corrugated metal converter-like diffusers. Now it runs like it did with the D&Ds, but there is no sneaking out of the neighborhood- it's loud- all the time. As a point of reference, one pardner of mine has a Heritage with open Hookers and another bud has a Roadstar with open 2" BUBs. Mine is comparable in volume db. The signature "blap" sound of a parallel twin is back, too. I liked the sound with all the baffles out and the diffusers in. The loss in performance was too much though. If I had a do-over, I'd take out all the baffles and the choked down section at the coupling and leave the diffusers in.
