Does anyone know what the ratio of top gear is for both the 400 and the 450? The reason I need to know is I have an 89 TZ250 chassis and both engines available to me. The 450 engine is on a shelf in my garage and the 400 engine is in my dirt bike. I got the 450 engine for the TZ chassis before I realized it only has a 4 spd tranny, which has me wondering if I should put the 450 engine in my dirt bike and use the 400 engine in the TZ. Any help would be greatly appreciated.