VW Scirocco engine in Audi Fox
Yes, but... I'm guessing you're likely trying to install a more powerful engine, such as the VW 16v from the later Scirocco mk2 ('83 to '89, and I think the 16v was available from '85 or '86). The basic blocks are very similiar; on earlier engines most if not all bore, stroke, and bearing dimensions are the same in same years and displacement, allowing one to use Audi connecting rods (stronger the the VW rods), and some other assorted benefits. Your first major complication is the crankshaft. The VW engine and transaxle is oriented transversly, the Audi's is fore and aft. Different transaxle and entirely different clutch mechanism. The Audi's clutch is fairly traditional, but the VW's is sort of reversed, with the pressure plate operated by a push rod running throught the center of the mainshaft. Result of which is; the crankshaft nose is different. You'll either need to machine the VW crank to mate to the Audi clutch assembly, or swap the Audi crank into the VW block. For reference, I strongly recommend Bentley Repair manuals; these are basically factory manuals sold to the public. For more and better information as to your specific intent, I suggest you try to find local VW or Audi clubs, or a really experienced VW/ Audi repair shop. A good mechanic who has been worked on these machines for years can probably help you get targeted on exactly what you will need to acquire to do the exchange. As I said, it's helpful that VW and Audi are so closely related, I'd guess it's a fairly simple process, bearing in mind that "simple" in context means an engine teardown and rebuild, installing the correct fuel injection and engine management components in the Fox, etc. And finally, if you do this swap; don't forget that more power brings other complications. You'll want to upgrade your brakes at least, and probably other suspension gear. Hope this helps, good luck.