I compared the Crower 2(improved), Crane 16, and Crane 18 in two charts. The first chart shows them at 11.5:1 compression, the second is 12.5:1. At 6000RPM, they all gained about 4-6 HP. The only noticeable difference is they hold a little more HP at higher RPM. The 18's @ 11.5 begin to drop off at 6000RPM, but at 12.5 they hold it until 6500RPM and don't drop off as drastic. The other two still begin to drop off at 6000RPM, just not as drastic.

Here are the charts:
11.5:1 Compression

12.5:1 Compression


I have a question Skrilla and I were wondering about. On Crane's website, they have the lift listed as Gross Lift, is that the lift including the 1.7 rocker(assuming that's the ratio), or is that the actual lift of the cam lobe? In the program, the lift it requires is lift at valve. For instance, the 16's have a lift of .374"; if that's actual cam lift, then the lift at valve would be .6358" with a 1.7 rocker(.374x1.7). As you can see, that makes a huge difference, a 12 hp difference at 6500RPM, according to the program. I'm kinda guessing that since it's 'gross' lift, it's everything included(rocker & lobe), but I want to know for sure. TIA

~Luke
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1969 Cougar - 11.91 - 380HP
2007 GSXR 750
1999 OZ - SOLD - 15.26 NA - 14.71 on 75 shot