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Pro Twin 120" Sport Touring Performance Package


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How do you prefer to handle your core heads and cyls?*
What color is your engine?*
Price: $2,918.03
Item Number: PTB-120-ST
Manufacturer Part No: PTB-120-ST
For use with all models.  Requires the use of a 4 5/8" stroke crankshaft. Package includes new cylinders.  Case boring is required.
Kevin uses this build in his own Dyna Superglide and a FatBoy. Many of our customers are using this motor in their FLH bagger type touring bikes because of the incredibly low rpm torque and dependability.  The increased stroke provides a better mechanical advantage through rod leverage and the results are much higher torque figures at a lower RPM. Mellow 2,000 RPM cruising is possible with plenty of power on tap for explosive throttle response through the whole mid-range and upper end. 
110-120hp | 125-135ftlbs | 40+mpg
This Premium Performance Package includes:
  • All parts and labor for complete headwork
    • Heads are fully ported and blueprinted to Pro Twin standards
      New 1.900" intake and 1.570, 1.610, or 1.625" high tuliped valves
      Custom fit manganese bronze valve guides
      Fully radiused valve job
      High performance/heavy duty dual coil valve springs with titanium retainers
      Viton valve stem seals
      Calibrated valve seat pressures
      Machined for 1 manual compression release per head
      Compression releases
  • Head gaskets
  • New cylinders 
  • Cylinder boring and honing - custom fitting pistons
  • Lightweight forged pistons
  • chain drive cams
  • Ez install pushrods and conversion tubes
  • Premium lifters
  • Top end gasket set (you will need to purchase your cam cover and oil compartment related o-rings seperately unless you are purchasing gear drive install kit)

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Product Reviews

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Thank you HQ!
Guy Dalton (Ohio) 8/25/2010 5:42 PM
Doug and Kevin, I am taking the time to write over a year after putting together the 120 ST build using HQ supplied parts and headwork. I did not write this last year as I wanted to see how the engine "lived" during a year of hard riding. It is easy for someone to say the bike runs great right after the build, but I wanted to give a true assessment after a true "break-in" period. I First, let me say thank you for all the conversations and for supplying a top notch product. I have done builds in the past, and many of them were science projects, using a part from here and a piece from there. This is the first time I have done a true "kit build". When the parts arrived, they almost looked like jewelry to me (my wife says I am a sick man), Everything fit and assembly was easy and the bike fired almost on the first turn. I self tuned it initially and rode over 18,000 miles last year, from north to south, at elevations from sea level to over 10,000 ft and ran the engine on as low as 87 octane fuel. It has seen temps as high as 110 and living where I do, has been ridden in freezing temps. The engine has performed flawlessly. I finally had the bike professionally tuned after 20,000 miles on the 120, and it came out 125hp/144tq even with that many miles on the engine. I am one very please rider. It is one thing for a person to say their build turned out great and they are happy when they only ride 3-5k miles a year. It is a whole different story if you are one that rides a lot of miles, and far from home. I needed not only performance, but reliability, and the HQ package has delivered both. For those considering Head Quarters for parts and service, don't hesitate to go with their kits. All components are matched, work well as a package and the results are repeatable and the engine is reliable. Go with their recommendations on everything (including all associated parts) and you cant go wrong! Thank you for exceptional service and parts!