I worked for a very high end race shop for over 15 years, and the only way to do this correctly is to use a lifter truing fixture such as those made by BHJ to relocate the lifter bore angle and location precisely, otherwise you will wipe the lobe off the cam. Once that is done, the lifter bore can be bushed and re-sized. Since these lifter bore truing fixtures are only available for the more common engine like small blocks and others, someone is going to have to pony up some big bucks to have one made. At this point, it probably will be cheaper to get another block.
I know of people who have tried to do this without these special fixtures and the results were high percentages of failures.
