Many(most?) states used the engine number on the title as the VIN through 1955. Some used the unit serial number. I've not personally dealt with a '33 so I could be wrong but I believe your engine number will be on a machined boss on the passenger side of the engine. On my 38 it's behind the distributor. I think the '33 is by the fuel pump but I could be wrong. If I am someone will correct me. I have no idea where the data plate containing the serial number is mounted on a '33. Someone will be along soon to provide that information.

Hi Victor

Everything Tiny says is accurate.

However, if you are looking for the car VIN (serial number) to register or re-title the car under that number, or some such thing...

I believe it is on the main sill (floor) just inside the door on the passenger side, possibly under the front floor mat.

Hope that helps, and hope someone corrects me if I'm wrong.  🙂