Fiat used different engine codes for the different models of the 850, which are cast on the right side of the engine.
Motortype Motor Seat

De motorcodes zijn als volgt:

Model Enginecode PK kW HP Bore Stroke Capacity Compr.Ratio Carburetor_1 Carburetor_2
Fiat 850  Berlina 100G.000 34 25 34 65,0 63,5 843cc 8,0 Weber 30ICF6 Solex C30PIB4
Fiat 850  Berlina 100G.002 37 27 36 65,0 63,5 843cc 8,8 Weber 30ICF7 Solex C30PIB4
Fiat 850  Special 100GB.000 47 35 46 65,0 63,5 843cc 9,3 Weber 30DIC1 -
Fiat 850  Coupé 100GC.00 47 35 46 65,0 63,5 843cc 9,3 Weber 30DIC Weber 30DIC1
Fiat 850  Spider 100GS.00 49 36 48 65,0 63,5 843cc 9,3 Weber 30DIC Weber 30DIC1
Fiat 850  Sport Coupé 100GBC.000 52 38 51 65,0 68,0 903cc 9,5 Weber 30DIC2 -
Fiat 850  Sport Spider 100GBS.000 52 38 51 65,0 68,0 903cc 9,5 Weber 30DIC2 Weber 30DIC11
Fiat 850  T 100GF.000 33 24 33 65,0 68,0 903cc 7,2 Weber 30ICF15  
          
Fiat 133 100GL.000 44 32 43 65,0 63,5 843cc 8,8    
          
In case you are searching for something special:
Autobianchi A112 (903cc) A112A.000 47 35 46 65,0 68,0 903cc 9,0 Weber 32IBA10   
Autobianchi A112 (965cc) A112B1.000 48 36 47 67,2 68,0 965cc 9,2    
Autobianchi A112 (982cc) A112A1.000 58 43 57 65,0 74,0 982cc 10,0    
Autobianchi A112 (1049cc) A112A2.000 70 51 68 67,2 74,0 1050cc 10,4    

I am still looking for missing extra information and will add to / expand it in due course.