at 4.15 Stroke, 4.28 bore, Vcyl= 978cc, reduction needed is 5.7cc for 0.5 CR increase (-.023"). Minor amounts of milling such as this will not cause other alignment problems. Our SS hemi's are decked about -.500", the heads another .040 to .065"- combine that with angle milling and milling the intake face- THEN you have some engineering to work through.