Indexing COX cylinders

This is a thin wall a Old thin-walled cylinder those have the taper inside cylinder And possibly has two bypasses its must be a no 1 If so it is a very good cylinder similar with the golden bee black widow I think sometimes the 1 is almost invisible on old thin cylinder the steped one has number in a difrent place Sometimes they don't exist like a cylinder with the screen mesh Once I removed the screen I  We can see the spot welds and i saw this small opening that I have rarely seen this cylinder has no SPI at all the cylinder in comparison. Wit a normal ex port has almost no sub piston induction, a very small opening Almost invisible but you can still see it with a light in the engine crankcase