I have been in touch with eddie today...the acetal/delrin black backs will be available for the EK 8 series blockas as of next week....I wonder if Santa can stop off in Slovenia for me!!
The fins are not that deep and look as if they were brazed onto the block rather than machined out of billet. It's just a bit rough looking. A lot of water will flow over the fins not thru them. I'll let everyone know in a few weeks how it compares to the EK.