Another bit of trivia for you, the 1.8 bottom end on a carbed motor is exactly the same as the GTI. And the 1.6 carb bottom end is also the same, but with different pistons & crank to reduce the cc from 1.8 to 1.6. It even has 1.8 cast on the block

Oh and the 1.6 and 1.8 carbed heads are the same too. As pointed out by several members the 8v GTI cam will fit into the carbed heads for a nice power increase.
The 1.6 & 1.8 carbed exhaust manifolds are also the same, but the 1.8 downpipe is the same bore size as the GTI at the end, so a GTI exhaust system from the front silencer back will fit straight on. For a 1.6, you fit the 1.8 carbed downpipe & GTI system.
The other option is to fit a full GTI system from the manifold back, which also bolts straight on
