I have a 2011 FLHTK on order and am planning a few adds to it right off the bat. The current plan is to put V&H power duals head pipe, V&H fuelpak, Screaming eagle stage 1 intake and screaming eagle slip on mufflers. Mufflers are a low restriction but not louder. The V&H tech rep sid most of the performance gain will be on the top end due to the free flowing exhaust and not much at lower end due to the low back pressure in the exhsust system. Would using the stock exhaust mufflers increase the back pressure and result in torque gains at lower RPM?

I am also lowering the front and rear because I am 5'7" and want to be able to flat foot at stops.

Higher end performance figures are an abject waste of time and money unless you're a serious drag racer. You'll never use that power on that section of the RPM band, and the entire concept is only useful for bragging in a tavern.

I chose Screaming Beagle pipes, a 203 cam, a lighter valve train and a race-tuner for a dyno run. Betty 'comes alive' from about 40 to 80 MPH, and that's exactly where I want her. I don't drag race, but I do bring her up to speed on acceleration ramps and I pass slow farmers. So do you.

My dyno graph shows an immediate up-tick to max torque and BHP off idle. It's a flat curve(s) of 100/100 until they cross at 5,500 RPM. No stutters, or dips and I'm nowhere near the rev limiter. I can let her sit at a long stoplight and never blip the throttle like in the old days. She accelerates cleanly from there.

More to the point, no matter what system you choose, you need some back pressure. Newbs are often surprised that bolting on straight pipes reduces both torque and BHP. I even left the scavenger cross-over on Betty. She's plenty loud, throaty and more to the point, I actually get all of the performance I paid for.

Thanks, that's why I posted the question. I know that the head pipes without the cat significantly reduce back pressure, and back pressure is necessary for TQ and HP. The question, which may be difficult to answer, is whether the stock mufflers would produce a desirable back pressure. I don't drag race, could give a rat's ass less what other people think about my set-up, but want to get the best performance and reduce the lean running heat. May call the V&H rep for his opinion since I will be using their head pipe and fuelpak.

I'll reply to my own post. I just spoke to the V&H rep who said I was given incorrect info before on the selected head pipes. The head pipes I am instaling are not a true dual, instead a 2-1-2 with the expansion chamber which does create a desirable back pressure. He advised againts the stock mufflers because they have too much restriction and felt the Screaming Eagle slash cuts are a good choice. This set up will create the performance gain in the lower and mid range of PRM, which is what I want. Also going with the V&H naked intake rather than the SE.

My 2010 limited 103 ci came alive after I installed the powerports and the tri-ovals. Lots more low end and midrange. We usallyy ride 2 up and really noticed the difference in the hills. Lots less shifting and only draw back is a little loud for my passenger. Runs great. deacon

I personally would leave the stock header pipes on it and go with the screamin Eagle mufflers.The mufflers are restricting the exhaust,not the header pipes.I would also buy the Ness Big Sucker aircleaner kit.The big sucker includes a K&N filter, the screamin Eagle intake kit does not include a K&N filter anymore, they cheaped out on the kit,which means you will be spending a few more bucks for a K&N replacement filter on down the road.