Hi. I am told that early T110s ?1953/54 had iron heads. looking at my parts books for these years, I see that 6Ts had 4 main head fins and T110s had 5 fins, but it is not obvious if these are alloy or cast iron. I ask because I have a 650cc engine with T110 cases and a 4 fin cast iron head and would like to know if this is a missmatch or not. Also am I correct in saying that the port diameters and valve sizes would be larger on the T110, compared to the 6T.