[Keithc8]

This trying to sleeve a 390 block to a 427 bore is a waste of good time and sleeves. You will have very unstable block that will not take much HP and that defeats the whole purpose of having a 427. Save your money for a good block or build a stroker 390 or 428 block. To sleeve a block properly you need to bore every other hole and install the sleeve with no more than .001 press and then bore the other holes after these two sleeves have been installed and install those two sleeves. The 427 is famouse for cracking between the cylinders when sleeved but done right it can be made to work with an original block if done right. We have had to do several ofr NHRA compitition but no more since the good blocks are available. Just my two cents. Keith