Getting interesting!
I measured my ports, intake port internally 31mm, externally horizontal 34mm and vertical 35mm, so its oval. Intake manifold horizontally 28mm and vertically 29mm, oval too. I get these measurements no matter how many times I measure.
All mesurement are +/- 0.2mm accurate because of all kinda cast snots.
Head is out of -80 (3T)TT-132 LB.
Classique71: can you measure your exhaust port and valve size? Mine was 25 X 31mm and normal stock valves.