I have a "new" TOP Novarossi TN12S1 engine, I believe it was manufactured in 2002. The specs on the engine look like a current model, except it has a standard head. The description says this is a great off-road engine. If I replace the head with a turbo head will it then be a great on-road engine? Are there differences in the timing that I will notice if I put this in an on-road car?