You may be able to bore your existing m/c out to 7/8. Should be much cheaper than a resleeve and then good as a new one. I recently picked up some small bore mandrels for a Sunnen. If my 3/4" m/c doesnt clean up well enough to use, it will be bored and honed to 13/16 first, and then 7/8 if I goof. If nothing works, then it gets resleeved. Right now I dont have anything to loose, since car is a long way from completition and having the equipment to play with, its hard to pass up. In the end, if all I need is a new master cylinder to finish the car, i can justify the expense.