T1 fuel injected engines vs T1 carbureted engines

I have just bought a 1975 1303S (Super Beetle) in Sweden and it has a
1600 carbureted engine (type AS). In 1975 all Beetles sold in the US
had Bosch L-Jetronic fuel injection, and when looking at replacement
engines it appears that the long blocks are different for carbureted
and fuel injected engines. Does anybody know what the difference is? I
am curious since I intend to replace the carburetor with the
L-Jetronic.

Thanks,

Jens.