Ross, I generally don't like to recommend motors to anyone since we all have different expectations. That said i will say that the k&B 65 Sportster is a somewhat different animal. It was made and introduced in the early 80's and was cursed by that timing as cheap low oil fuels were introduced at about that time. A couple of runs with the stuff and a lot of plain bearing motors were toast. You can buy a lot of them cheaply and they run badly as Dar has stated but he didn't give any history on the motors that he saw run.
With that out of the way a properly broken in 65 will not set the world on fire with it's high top end and to expect such is un realistic. It is made to not exceed 12K and contrary to it's running instruction of using an 11 inch prop , really does it's best work on 12 and 13 in lumber. Rpm numbers on 13 in props are usually in the high 9's to mid 10's but you are getting a fair amount of thrust without over heating as you would with a lot of other 60 sized motors. Fuel econemy is very good and running and idle charicteristics are good. Cavat is to make sure that you never run the motor lean, and there is no real reason to. That said you will have a very long lasting motor and it will pull your 8 pound model in a realistic manner. Remember the motor was for all purposes designed as a cheap beginners motor, much llike the OSLA series or the TT GP series. As is normal for most plain bearing motors there is a run in period, Do not try and force the motor to perform more then it can at the beginning. They do take a little time to break in but properly done they are a one or 2 flip hand starter and will reward you with years of service.
dennis