I am not finding an 86sx chunk to put in 86 250es on eBay or the classifieds.

There are plenty of 85s on eBay .

Could I get a 85 rear end and have the case cut to fit the 86 axle tubes, I don’t just mean bolt on I mean really be supported by the register . I read in the forum you can make it work with a grinder , this sounds like a bad idea if the hole is all wallered out and the bolts are holding all the load.can this be done correctly.