Harley Twin Cam Big Bore Kit With Ported Heads 103" Stock# 09262013 on 2040-parts.com

A great performing 103" Harley twin cam package including all touring models 2007-2013

The  heads and cylinders are beautiful dealer takeoffs. A quality Harley twin cam 103" performance big bore package setup for .550-.575 lift cams. This isn't your factory 103" build. I've had many customers use this build and are pretty amazed at the difference between this kit and the factory build. Performance products for a powerful and dependable build. This is a full service ported and polished set of heads .

Harley Twin Cam Ported, Polished and Flowed  Performance Heads, -06 series heads with beehive  springs good to .580 lift cams, Ross forged big bore flat top piston kit and cylinders. With over 35 years of machinining and polishing service to the performance enthusiast. I still run a one man shop with my number one priority "Quality" These are clean dealer takeoff heads and cylinders, with  1.900 oversized  Intake,  & 1.610 oversized  exhaust valves. Each set of heads are flowed on the  flow bench to assure a high flowing set of heads.These heads flow very high Volume and Velocity which will give you great performance both on top and through the gears. Very hard pulling big bore package that average 102-108hp with 105-115fpt depending on your setup.  The heads have a very high lustre on the exhaust ports and the combustion chambers to reduce the carbon buildup and run cooler.  The intake ports are finished to 80 grit, to atomize the fuel.The intake ports are ported  for excellent fuel transition through the port. You would'nt want highly polished intake port, as the fuel would stick to the port walls. The ports are port matched with precision cnc machined porting rings. I use manganese bronze valve guides, which pulls the heat from the cylinder and valves and offers extended life.. The  1.900 intake valves are machined with a muti-angle profile.  The 1.610 exhaust valves are also  machined with a multi-angle profile for added flow. The port side of the valves get a swirl finish. This helps to atomize the fuel as it enters the combustion chamber. Remember, the liquid part of gas does not burn, it's the vapor. It needs to be atomized. This is why you can have a really strong motor, and still get 50 mpg. "Efficiency"   The valve seals are new Viton seals which are the best for wear and heat resistance. The heads are decked .015 to create a 9.9:1 compression with the Ross forged flat top pistons and a stock big bore gasket.  Excellent compression for a powerful and dependable street bike. High enough compression for great power, but not too much to create starting and octane issues. These are custom manufactured for Dunnperformance by Ross piston Corp. We were in search of the perfect street bike compression piston, when we teamed up with Ross to create this great setup. The rocker side is machined .005 to ensure a good seal.  I would recommend a .550-.575 lift cam with a .240-.250 duration with these heads.   These heads are ported to increase velocity and volume which will give you much more torque and top end. The air opens up very fast. The increased air flow through the entire lift range increases torque. Not just on the top lift. Torque is that great feeling you get when you twist the throttle. I don't like huge ports because it slows the velocity. Think about it , you could bore a huge hole, lots of volume,but that volume would move very slowly. Result ,no torque, no bottem end. Most of us don't ride at 6000 rpm's.They are meant for a strong running street bike, not race engines. Of course we all like to twist the throttle every now and then. You will not be dissapointed with the power and torque you get from this setup. The cylinders are bored  with torque plates and honed to fit the Ross forged big bore pistons, that are supplied with this kit.  You will need to increase the jet size on carb models or increase fuel, through fuel management on fuel injected models.The heads are cleaned and lubed before assembly. Finally I test the valve to seat for a tight seal. They are dealer clean takeoffs heads, ready for your project.  I have had several people ask why I don't sell the 106" and 107" big bores. The reason I don't is because the cylinder walls get too thin and cannot dissipate the heat fast enough. I work with several builders around the country and have heard many nightmare stories of piston and cylinder issues with the 106" and 107"s.   These are an outright sale, no down time, no trade required. Cores are accepted if you desire. Buy with confidence, Money back guarantee.  I have sold many of these on Ebay with 100% feedback. You won't find another big bore kit at this price with all the detail work I have put into them.   This Dunnperformance big bore kit will produce incredible, clean power through the gears. Thanks, from Dunnperformance    I will ship to countries outside the U.S.  Please ask for shipping quote outside the US.  

 Please visit me at my website: Dunnperformanceheads.com  Any questions you may have, always happy to help. 303-718-7146 or

 303-814-8913              Shipping, handling and insurance are all provided in the shipping cost.

A few testimonials from some recent customers.  Just remember a stock 96" motor will pull 65hp with 68fpt. at the wheel. You will be looking at a 35-40hp gain with a 35-45fpt. The increase in power is dramatic. Around 100-105hp with 110-115fpt on this 103" kit    Built to be  Powerful and dependable.    

Thanks for doing such a great job on the heads!!!  My mechanic and his machinist were impressed w/the quality. My son nicknamed the bike the “Beast”

We did 97 hp and 98 fpt on my fxd with your 95” big bore kit, and a set of Andrews 54 cams

I just wanted to say thank you for a high quality product! I am super pleased with the massive increase in power and torque with the new 103 kit. It is literally like night and day. Thanks again and keep up the good work!
Roger

This is an update on the 103" big bore and stage II heads I purchased from you.  Totally impressed with the work on the heads as they really woke up my '07 Ultra classic. The torque is awesome and is "right there" as soon as you move off idle. This thing pulls HARD and evenly from start to finish. The 103 jugs you bored were on the money as far as size and finish. This was my first Harley-Davidson build and went extremely well  and easier than I expected. You furnish an excellent product and great advice!