I picked up a pair of #47 heads for $75 from a running motor for my 350. They are listed as 1.96/1.66 73cc or 8.6:1 compression. I got them home and cc'd them this morning. 83cc on all 8 chambers! What the heck? I have 7h1 heads with 91cc's. I was hoping to go from 7.6:1 up to 8.6:1. With 83cc's I'm looking at a little over 8:1. I drove 3 hrs to get them. That sucks. I did visit some relatives nearby that I haven't seen in a long time. Otherwise it would have been a waste of time and gas...and $$.