d7 Cook, You can get the I.D. on our sleeves @ 4.187 or even smaller if you want. We make most of the sleeves from semi blanks anymore because of all the different blocks we manufacture. Also different stroke and rod combinations require different clearances on the bottom etc...etc...We don't charge extra for this on a new block but keep in mind that a 4.700 O.D. sleeve and a small I.D. will add a few pounds to the block weight if this is a concern for your application. As stated on here we like to have a min .100 wall for blown and hi output turbo and or nitrous engines. We know that we have customers that have gone to +.060 (4.560) and have not had any issues. It all depends upon your cylinder pressure. If you have any other questions either send me a PM or give me a call 562-869-1518. Ken Black