if your getting a lot of oil around the boot, you have a torn boot or its not sealing properly and that will cause an airleak.

I would send it out an get it pinched, you will get a better idea of how well it will run. I havenever ran a jammin engine so I can't tell you how the powerbands compare, but a properly tuned Go will give you a very nice powerband and the 5 port will give you great bottom end punch.

As far as people having trouble tuning the engines theres a couple of things i would liek to say, the carbs are very good and the engine tune very easy. you just have to get used to how much you turn the needles. A full hour on a go carb can dial you out, remember to use a gentle touch.

Also until the top end is fully broken in (no more metal pinch) the engine will not run its best unless its in the 250-260 range. It is best not to push that hot before the top end is broken in unless you have to.

One other thing I noticed at the track with a buddy and this is important going into winter is he fired the engine up and then began revving it really fast to warm it up. That puts an enormous strain on a fresh engine to try and make it spin r's completely cold. Give the engine short burst of medium throttle on the box before you put in on the track and let it get a little warmth in it first.

Also never try to run your engine completely out of fuel, and also be sure to set the piston at BDC after your race. Its those habits that add a lot of life to any engine.