Looking for a little advice about swapping a D15A1 for a D16A6 for a 91 Civic intended for dirt racing. The engine needs to look original on the outside to follow the rulses but they never check the details. So can anyone tell me about swapping these motors and what I should do and expect. Also what is the best bang for the buck when comes to getting top performance out of the D16A6 engine. Any other tips for building a strong racer would be welcome.