The chimney on my roof needs repointing and some of the bricks are cracked and need to be replaced. I have roughly the same number of unused bricks (left over from the original construction) as cracked so I figure it's likely that I missed a few that will need replacement, too. The bricks are 47 years old and no longer made. Also, the bricks made today are shorter (7-5/8" long vs. 8-1/8" long for the old ones). Is there a good way to handle using some smaller bricks or will I have to have the whole chimney and all the bricks replaced? What issues would a mason have with this project? I'm perfectly willing to participate on the ground mixing small batches of mortar or whatever. Incidentally, the bricks and mortar are brown which I would like to have again.