Sorry about that 22racer, the 5port puts out more power down low and works well in truggies, the 5port is generally a more forgiving engine as far as tune, pipe clutch setup. the 7port is amazing in the mid to top and still has a strong bottom because it is a 5port engine with a tri exhaust. It takes a little finer touch on tune and clutch but when setup properly it is an amazing buggy engine. Setup right in a buggy the 7port will have endless top and be able to spin all four tires coming out of a corner. It makes it kind of a tough decision but i would say think about the tracks your race at and the level of traction, if they are high bite you may want the 5port, if they are medium traction you may want the 7port.