Some alloy sump plate issues to note.... There are two popular types on the market, the billet type (quite swanky!) and the cast type (equally effective but not quite so swanky!). Both types have thicker bodies than the original type so you need to consider how to secure them to the sump. Ideally you should use longer studs so that the whitworth end screws fully into the crankcase casting. Most people use whitworth allen caps and screw them through the new sump into the alloy. I think this is a bit risky as the internal threads in the crankcases are short and prone to stripping anyway. Unless you are very careful making sure your threads are good, and you use the full length of the thread, the potential for stripping is quite significant. I would recommend using longer studs with standard nuts and shakeproof washers - don't use nylok nuts as these grip the studs so tightly that the studs tend to come loose before the nuts. Most people have binned their original strainer by cutting it off the original sump and replacing it with an independent mesh strainer sandwiched between two gaskets and the original sump plate. One further point is that fitting a magnetic sump plug to the original plate magnetises everything the plate comes into contact with, which may include the suction pipe, depending on what type of strainer you use. Ideally the strainer should be stainless steel to prevent this.