Heads height 2.0, 2.2 - 2.7 ... ?

[964-RSR]

Hello,

I can't find the original height of heads for a 2.0L or 2.2 - 2.7 and the lowest height suggested by the factory.

I have measured my 2.0 heads and found 87 mm between the gaskets surfaces.

My 2.4 heads are 87 mm too but I have to substract the height groove where the O ring gasket goes (- 2.5mm) => 84.5 mm

I can't find why there is a difference between the height heads !

I don't have measured the height of cylinders 2.0 and 2.2 - 2.7. May be there is a difference ??

Thanks for your help.