As simple as it may seem, I see people are searching for where the chassis number is located on the Alfa’s. Every car has a different location. My 6c2500 had it stamped on the chassis on the cross member just in front of the radiator (or was it in back?) The Bertone number is stamped on the chassis just above the location of the Alfa Romeo number. The Pininfarina number is stamped in the trunk floor.
The Alfa Romeo number for the 750-101 cars is stamped in the firewall, on the passenger side right above the heater air intake hole. It will start with AR and then the number.
Just a little clarification now and then doesn’t hurt. Please refer back to my article called the “Chassis Numbers and the Hidden Number” for further clarification.