http://ferriday.co.uk/cnc/decompression_plates.shtml
I have used De comp plate no problems at all, but you must have the top of the block skimmed and the face of the head skimmed, or your wasting your time and money, I think most people assume you just wack in a De comp pleat and a new gasket and away you go..... Wrong this will only end in failure......

Steve