Ok all you gearheads, I just picked up a 1997 MXZ and it was rebuilt from a bunch of different sleds. I know the motor was just rebuilt with stock 670 pistons and the case is stamped Type 670, but the head on the motor is red. All the 670's I have seen have purple heads and the 583's have red heads. So whats the difference in the two cyclinder heads other than color?