Ok.... first of all you want 40:1 not 1:40 mix.... I have had the best results with the APC 18x6W prop - It gives about 500 rpm more than any other prop I have tried (Mejzlik 18x6, Biela 18x6) As far as needles are concerned, I have leaned them out some, maybe between 1/8 to 1/4 of a turn... Right now my engine spins the APC prop at 8500 rpm and it sounds very happy - I tried leaning it out even more and have seen almost 8800 rpm, but there is no need for me the run that lean.... 8500 rpm is plenty to pull my GP Stearman around....[sm=tongue_smile.gif]