Euro Heads and USA Heads, are they different?

[28rusblue]

Hi,

I noticed their seems to be a few different part numbers on 930 3.3 liter turbo heads.

Does anyone know if all 930 3.3 liter 350RR cylinder heads from 1978 to 1989 are all the same and were created equally.... (port sizes & valves sizes)

Or.... did the Euro rest of the world spec turbo cylinder heads have bigger ports /valves than the cylinder heads that came on the de-tuned USA spec cars?

Do the earlier 1978 and 1979 year euro 3.3 turbo heads have bigger ports or different size valves than latter 1980s turbo cars, just like the heads on the earlier 911SC cars?

Any info would be great.

Thanks,
Greg