RE: What is the original Cox Black Widow cylinder?
The older BW's did in fact come with the #1 2 big exhaust ported cylinder. The cylinder with the twin slits on each side really is not that bad of a cylinder. And yes some BW's came with them so it could very well be stock. The real performance is in the porting. As long as it's a twin bypass ported cylinder( ports inside of the cylinder ) it should work real well for you. You will lose alittle without the SPI though.
Later,
Tim