For both EFI or Carb Models

The above photo is for visual representation only. Parts may vary slightly for different jobs.

Our 120 motor package uses a set of 4.065” bigger bore cylinders and will require a 4-5/8” stroke crank using standard length rods along with a set of Head Quarters HVP cylinder heads and cams.
You will need to purchase a crankshaft assembly from a specialist like Dark Horse or your HD dealer.
All years of the Twin Cam motors will require case boring to accept the larger bore cylinders. Instructions are supplied with the cylinders and it is very basic machining for anyone with a milling machine, angle plate. draw bar and boring head.
The forged CP Pistons used in our kits are a Head Quarters exclusive featuring a dish in the tops to accommodate the use of stock heads and permit us to create compression ratios varying from 10.5 to 11:1 depending on needs.
Doug (HQ owner)  uses one of these motors in his own Dyna Superglide. Many of our customers are using this motor in their FLH bagger type touring bikes.
The increased stroke provides a better mechanical advantage through rod leverage and the results are 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. 

Sport Touring package includes Head Quarters HVP ported heads and cylinder boring, forged pistons for 10.5:1 compression ratio. Cams will be one of our 575 grinds, part number depending on year and cam drive system.
click here for-> Build list for Above Kit

Sport package includes Head Quarters HVP ported heads and cylinder boring, forged pistons for 11:1 compression ratio. Cams will be one of our 600 grinds, part number depending on year and cam drive system.
custom build upon request
 All above packages include MLS type head gaskets

Power and fuel mileage expectations.   Torque       Horsepower        Mileage
Sport Touring                                          140-150        115-125            45 MPG
Sport                                                        145-155        120-130            45 MPG