KB237's usually make nearer 9.6--9.7 with a trued up 452 head deal--get the distributor curve just right and premium pump is easy without the quench saga--IF you do a perfect quench deal it gives you an edge but normal dudes in the back yard can run fast and without trouble by getting the curve right ( many ways and folks to do this like FBO) ---I agree that NO way with 10% ( and SOON to be 15% alky ) that you can run any more CR than this and be safe--quench will help but the gas we buy WILL be 15% sooner than you wear that thing out so get ready and plan ahead.......Turning the timing back to keep a higher CR from killing itself knocking--just guts it---no way around it...........