I am shopping for a micrometer. What size should I be looking for? Right now I'm just starting a rebuild on my 327. I know what I need there, but I am wondering about rearends, tranmissions ect. If I get one that will do everything on the engine will it be large enough for the rest of the projects? Also, who has the best deal on them? Would it be Sears, Auto Zone, Discount Auto or maybe Ace hardware. I did not see any in my Jegs or Summit catalog. Thanks for your help!