I'm currently pulling off my heads as I have a compression problem and now I can get a good look at it's numbers and I'm now confused.  Not that hard really.  I thought they were ECG-B as it's a 55 CEBY 272 block and a bit rusty around there as it's in a ski boat that was neglected. 

Now that I cleaned it up I believe that it's ECG-S, definatley not B, but I can't find and listing on John's site in Cylinder heads, so I thought I'd throw it out there.  Attached is some photos that are pretty clear and also of the other markings on them for reference.  Any advice is appreciated and I'll try to get the valve measurements if reuired when I get them off, but I've run into trouble as I broke a lower bolt that is rusted in.

Cheers Whitey

My first V8!!

Brisbane, Australia!!