Hi Enrico,

If you are going to leave the head and compression stock, then get the RV10. If you are going to raise compression, then RV15 would likely be better. If Ken at Oregon Cams does not have these numbers readily available, then we can send you custom specs.

Make sure to measure your chamber volume and piston-deck height while your engine is apart, to obtain your actual compression ratio, then adjust it from there by milling the head (if not pulling the lower end apart).

Bigger valves and some porting work in the "bowls" of the head helps with power across the whole RPM range.

All the best,

Lou

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