IMO its best to keep the bore and stroke close to the same or even slightly more stroke than bore, and seams to be a proven combination over the years.
The longer stroke allows the transfers to be shorter, allowing the exhaust port area above the transfers to be increased without raising the duration numbers as high as a short stroke setup with a equal exhaust port area.
The exhaust port size above the transfers and its ability to remove the exhaust gases before the transfers open will make be one of the largest impacts on the output of the motor and its ability to have a good over-rev. If the exhaust gas pressure's are not brought down lower than the pressure in the crankcase the exhaust gases do not care which way they go and will travel down the transfers until the pressure drops low enough to allow flow to change direction and back into the cylinder. Every cylinder has this condition at some point in the rpm range but the better your exhaust port flows during the "blowdown period" the better the power will be at high rpm.
The problems with stroker cranks are piston speeds are increased along with friction and wear and port timings do increase on both the transfers and slightly less on the exhaust port, so if you do not have a stock like port timing, your port timing may be to aggressive for your style of riding. But some of that is offset by the fact that you have more cc's and with more displacement you normally have more lowend power
Hot rod has brand new long rod +4 cranks for 250.00 and that is a great deal so for the money its hard not to justifiy not buying one.
