Nice Bolt in Cam, no valve spring change required.
Gear drive cams do away with the cam chains & the tensioners that have the potential to wear out if unchecked & cause catastrophic engine failure.

S&S 509G Cams                                Part # SS330-0017
S&S Pushrods                                    Part # 930-0013
S&S Lifters                                          Part # SS330-0718
TechnoResearch Tune Key              Part # TR200053-M01
S/E Stage 1 Air Cleaner
S/E Mufflers
Stock Heads
Stock Throttle Body & Injectors

Power:-    76.0 -> 82.2 (6.2 HP increase / 8.2% increase)
Torque:-   77.6 -> 89.5 (11.9 ft-lbs TQ increase / 15.3% increase)