RE: props
maybe I'm typing to fast for your reading ability so I'll type this one really slow.........do i need to explain what 'In Same Said Engine' means too????
timing and porting set an engines power band, the range of RPM where it reaches it peak performance.
under propping to get higher RPM is fruitless in an effort to gain speed, it simply overheats the engine and causes it to lean out loosing even more power. over propping does the same thing, they overheat and lean out loosing power. IF your philosophy worked everyone would buy a cheap engine and put a 6" prop on it and go 200mph unfortunately it just doesn't work that way in the real would outside your imagination.
you mention diamond dusts, mine has a Jett 60LX w/ 8.8x9 prop @ 21K static, another club member has a Rossi 21 w/ 6x9 prop @ 28K, in your theory his same pitched prop turning 7 grand more RPM should have a higher top end speed then mine but again in the real world he's lacking by 15-20mph and is very lacking in launch power.
kc