$100 per HP rule?

Mase, a longtime VRCC contributor, has referenced the $100 per HP rule. Let's see how that rule works out with commonly available Valkyrie modifications.
Modification	$ (street price)	HP Gain	$/HP	Notes
Trigger Wheel	16	3-4	4	1
LaMonster supercharger	3,500	32	41	1, 2
Dyna 3000	285	3-4	81	1, 7
VMC exhaust	1,000	12	83	3
Web Cam/TBR cams	425	5	85	6
VMC heads + VMC headers	2,300	25	92	4
LaMonster supercharger/TBR pipes/rejetting	5,000	47	106	1, 2
TBR 6-into-2 Slashcuts	1,050	8	131
			====
Average			$78 / HP

Dogs
Nology/TBR Hotwires	439	0	n/a
TBR 6-into-6's	700	0	n/a
Cobra 6-into-6's	620	-8	n/a
Pretty close.
NOTES:
Prices do not include shipping. HP gains are from credible reports to the VRCC Tech Board.
1: The use of premium is required, so the cost/HP is deceptively low if you run regular now.
2: HP gains with a stock exhaust.
3: VMC quotes 12 HP gain on its Web site, but posts a dyno chart showing 16 HP gain on a stock Interstate. The figure above may be understated.
4: From VMC: "We have developed a system that will yield as much as a 25 HP and 20 ft. lbs. increase over your stock setup when used with VMC Performance Exhaust and Dyna 3000 ignition." Once again, these figures may be conservative. If so, hats off the VMC for not exaggerating.
5: The 142 HP figure reported here was achieved with some additional shop time/dyno time to find the optimum jetting, which I have arbitrarily estimated at $500.
6: It is reported that Web Cam offers a more aggressive grind which gives more power on the top end, at the expense of low-end power. I have not heard any reports of the HP gains of this more aggressive grind, however.
7: The Dyna 3000 allows for an increase in the rev limiter, which may be the key to unlocking real-world performance gains, as modifications (especially supercharging) frequently push the power band up the RPM scale. Additionally, the Dyna 3000 has a retard mode, which may be essential for a supercharger installation. In that regard, the $285 valve spring kit from VMC should also help unlock safe HP gains at the top end of the scale.

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