Well you know the saying if some is good more is even better.I was able to slot my pickup slightly adding maybe a couple of more degrees Now running at 7500 w/16x10 apc this means another 100/200 rpms.Keep in mind this is free power with no parts or expense.I hear no evidence of preignition and throttle responce is excellent.Incidently i'm still hand propping it.If anyone goes any further such as redrilling mounting holes etc. please post results.I'm pretty much satisfied right now so i doubt i'll go any further, as is it pulls my 12+ pound plane verticle very well and comes very close to hovering it, and this on a 90 deg+ day.