sorry to burst your bubble jmac but if diff shortening was so easy I and companys like craft ,bosnjack eng, scw and a host of others in other states would have not done hundreds if not thousands of repairs to diffs that have been done by the average bloke with a stick welder and a grinder . there is a very involved process to shorten a housing and keep it straight AFTER it has been welded and by straight I mean test bar straight. What's a test bar I assume you ask? its a ground bar that is put through the housing and is located in the hemisphere bearing diameters by precision bushes , then another set of bushes is used to test the alignment of the wheel bearing diameters in relation to the test bar and ultimately the centre bearings , the trick is every weld pulls the tube and in the case of a leaf spring saddle that's 4 welds on about 100 deg of one side of the tube, that makes for a banana diff that has to be straightened after all the welding is done , and did I mention that you have to keep the flange face of the wheel bearing end square to the test bar also . if this is wrong the diff will eat wheel bearings and chew out the limo cone splines . by all means have a go yourself but beware of the mistakes all the so called "experts" seem to make , then when you want it done properly (with a warranty I might add) don't winge and whine at what the engineering companies charge