One of the keys to what makes this such a high-performing kit is the R&R cast cylinder heads. While you could save a couple of bucks by using your old heads as core deposits for a set of reworked Harley heads from R&R, to really get big numbers your best bet is to go with the R&R Vortex-flowed cast heads. Reggie Sr. told us the trick to making horsepower and torque isn't only about stuffing as much air and fuel into the heads as possible; maintaining high velocity is equally important. The team at R&R has spent a lot of time designing, testing, and studying the cross-sectional flow analysis on their heads, so they know the direction and velocity of air at any given point.
Proper headwork is all about design efficiency. All of the R&R cast heads are CNC-ported. Reggie said that every cast head is different, and core shift (a variation of the size and direction of the core) takes place during the casting process. In the casting process the ports are undersized, so R&R can CNC-port every head to get the proper amount of cfm (cubic feet per minute) and velocity for each head. The problem with most heads is that the intake port has a long arc radius at the top but a short bend (almost straight) at the bottom. That short bend at the bottom is such a tight radius that it's difficult for the incoming air to bend around it, so the air ends up separating and ricocheting around, losing its velocity and ability to flow the entire valve. To solve this problem, most people will run larger valves to catch more air around the part of the valve that's flowing, but that still doesn't solve the problem of that short bend.
R&R's solution to the problem is the Vortex Generator, which has been around since the '90s. The Vortex Generator is a raised section of the port floor that splits the air and bends it around the short bend. The Vortex Generator is able to do this because its design creates a longer short-turn radius, making it easier for the air to flow around the bend, thus increasing velocity and flowing the entire valve. Because this head design is so efficient and flows the entire valve, not just part of it, R&R can run smaller ports and valves (1.94-inch intake and 1.625-inch exhaust valves) and still get the same cfm as those running larger ports and valves.
We had heard the SPP crew was going to be hanging out in the Phoenix area, taking care of a few errands before the Laughlin River Run. So we asked if they'd be interested in making a quick trip out to Southern California to install one of their 95 kits on one of our baggers. Then we'd put some break-in miles on the bike on the ride out to Laughlin and head over to the SPP setup in Bullhead City to have the bike tuned and dyno'd. The guys at SPP were more than happy to do the job. The base SSP Stage III 95 kit includes reworked H-D TC heads, cams with gear-drive setup, adjustable pushrods, ignition or Power Commander, bearings and gaskets, barrels, pistons, and rings and retails for about $3,214.