I've seen .008 differences in rods center to center lentgh on 426 Max Wedge and stock 440 LY rods, .003 on after market steel H beam forged rods I used a set of Oliver billet steel rods on one blown 426 street Hemi build and it had similar differences in deck hieghts, you really need to check the stroke also to help determine exactly where the problem is coming from