Does anyone know the size of an unmilled E31? Sorry, couldn't find it in my searching. Thanks...Robert

I think your question requires a little more specific detail, in order to arrive at an answer!

If you are talking about the head thickness, it is (as best I have been able to determine) just a hair under 4 1/4", or 107+ mm.

When I was looking for this info last year, I found that exact figures were surprisingly difficult to come by.

Thanks for the info Arne. Sorry, yes I was looking for the thickness...Robert

Yep, 4.25" is what my machinist came up with when I was building my engine years ago. All the (gas) heads are the same thickness as I recall.

Yep, 4.25" is what my machinist came up with when I was building my engine years ago. All the (gas) heads are the same thickness as I recall.

All heads are 108mm thick.