MCA supply steel cased bushes whereas Wassell supply solid phosphur bronze bushes. There are other suppliers. The outer size of all bushes should be the same. The inner is supplied in 0.010 increments. As Berger says, it is important to check the journal size of your crankshaft before fitting the bush. You need to measure the top v bottom diameter and front to back diameter on the inside and outside of the journal. Also look carefully for a lip at the outside edge of the journal which will indicate wear. I always have the crank ground if I find any ovality or lip. You can get away with up to 0.001" (1 thou) at rebuild stage but most would want to do better than that. If there is any wear in the bush as well the job really needs doing properly. You don't need to take the crank down to the next 010" increment, you can just have it ground round and concentric then ream an undersize bush to suit. I would not recommend doing this yourself unless you have engineering experience as this is one of the most critical parts of your engine rebuild. One course of action, if the journal measures Ok, would be to assemble the bottom end and measure the vertical play in the crank which, ideally, should not exceed 1 thou though maybe 1.5 thou would be the absolute limit; you may be lucky! Remember that the amount of vertical play will have a proportional impact upon oil pressure so this is one area where you shouldn't compromise.