I don't think they make .003 chains. If anyone would could get it, Mike at TA Performance can. He has custom chains made but $$$. I also would not depend on those figures. They get you close. You may have to buy one smaller and one larger and see what fits best. You are talking about tolerances less then .002. This can be seen in measured chains of the same PN. I remember doing Chevy's and pulling a dozen chains out of the boxes to get one that fits perfect. If you put a straight end against the cam/crank gears you measue the slack in the chain. I look for 1/4" of movement off the ruler. If you are degreeing the cam, use the wheel and get slack under 2 degs.