The cams I was shipped are a pattern used to set a land speed record on a 995 cc engine, I learned recently. Some figuring shows the long durations require a lot of rpm to work with some sacrifices in peak torque and volumetric efficiency. This can be a winning combination. It allows the engine to use numerically higher gear ratios and this gives more tractive force. This can more than compensate for reduced peak torque and VE. A few builders are taking the high rpm approach both here in the US and in AUS.
The downside if the high rpm method is a reduction in component life and good skills are needed to build the motor. In my case, I do not have enough money to replace a lot of parts. Also, the stuff is custom made and it takes a long time to get. Too, there seems to be a history of catastrophic component failure with these highly tuned engines. The lessons learned from this, as per engine setup, I will never know. I am pretty far removed from the "inner circle."
The original engine as shipped from Triumph had the rev limiter set at 7,300 rpm. The limit is raised to 9,000 rpm this year on my engine. Stresses on engine parts are often the square and sometimes cube of rpm increase. The 1,700 rpm increase increases stresses 1.5 to 1.9 times based on these ratios. The cutting edge builders are revving these things over 10,000 rpm. This increases the stresses 1.9 to 2.6 times over those at 7,300 rpm based on square and cube ratios. As seen by this, ultra high rpm puts bigger stresses on an engine. Did the Triumph engineers include enough factor of safety in their design and material selection to address this?
The 9,000 rpm limit requires some cams with shorter durations than the ones I have. The pattern development costs for custom cams make them real expensive. There is a cam shop that has been selling and working on bumpsticks for these motors and they have been doing it for years. The expert that is helping me is figuring out the cam characteristics I need with consideration for the measured flow in the cylinder head, the measured compression ratio, air density at Bonneville, and the desired peak power rpm that is in the mid 8,000's. Hopefully the cam shop has something close to what I need.
The approach is to use some serious thinking and work to develop a motor that will beat the big rats on a tiny mouse budget.