Any easy ways to ID a SB head?

J heads are most of the time early 360 heads or late 340 heads using 1.88intake valves and 1.60 exhaust valves, have heard that they can also bee machined as 340 transam heads wich are quite rare, the J heads are good heads and will flow just as good as a set of X heads if you install the bigger 2.02 intake valves:)