Identifying daytona cylinders

[BCRD]

I'm looking at buying some rd400 cylinders here in Canada. The guy selling doesn't know what he is looking at. He has a few daytona parts in his collection. How do I tell what year the cylinders are from?  Also I know the euro 2r9 cylinders are sought after. Are the Canadian 3j7 cylinders simular? Can I run them on my 77?

[SoCal250]

The 3J7 cylinders for the Canadian market are the same as the 2R9. The difference between the two is the EU version used 2 piece cylinder heads and two gaskets. The 3J7 used a 1-piece gasket and head similar to the US 2V0 design, but it is similar gasket thickness and cc to the EU version and the US 1A1 version. The 2V0 uses a thicker head gasket than the other RD400s.

The 79 and 80 Canadian cylinders are identical (same part). A 3J7 cylinder will have those letters cast into it. ID of the cylinder version is cast into the base of each part (see photo for an example of a US RD400F).