OK here is what I run 446 with E-head 84cc shaved to 80cc Arias 17.5cc domes these are the big domes 0 deck on the flat part of the pistion .039 gasket = 14:1 compresion 620-mp cam .090 valve to pistion clerance. I did modify the pistion dome only for the plug ,but you don't have to notch the pistion for the plug if you run Autolite AR3933 as thay do not have a protruding electrode. I found this out after I put the motor together.
Hope this helps