pushing the stock rod limmits


so ive been toying with a stock rod build.. ive done a few over the last few years just for fun, but im really getting to where I know im pushing its limits!!! just wondering does any one else build stock rod motors for fun??? not bsp motors!!! something with a bit more power
I keep the rpms under 6,000 and the others have lasted quite well... had one with a 14cc un-shrouded head, header, s/a carb, filter and it ran like a champ!!! then I have the one im on now... that I went the other way with.. shooting more for flow with the same carb and pipe as be for, un-shrouded the stock head with polished ports, (not ported!!! just polished) 2 nr carb spacers, nocked the gov gear off the crank, 1-3 rockers, and 18lbs springs... im thinking of milling down its head but just don't know if she'll hold???
A good share of the success or failure of a 'stock' rod has much too do with lubrication....ie: type of oil, level of oil, oil return hole, oil temp, bearing feed hole, ignition timing, etc. Too little oil will burn it up....too much oil will aerate and create problems. Breathing and flow would be of higher priority than compression with regard too longevity. Keeping it under 6500 and not 'lugging' it on the low-end would be beneficial. JMO
ooo im putting my bsp-ish motor back together screamnclones... for my shelf motor.... but I have the head off from doing other un listed head work... just trying to decide if I want to mill the head while its off...