It is the engine on the one hand and the wider wings on the other hand.
The 4/4 has been equipped with the 1.6l carburator engine and the narrow form.
The Plus for has been equipped with the 2.0 fuel injection engine and the wide form.
In the Paper by Charles Lofstedt in Miscellany he wrote that only the first 15 +4 were equipped with the 2.0 carburator engine.
If you send me your e-mail adress I can provide you the Fiat engine paper.
Cheers
Miklos
Last edited by Mkiss; 06/02/20 11:29 PM.
