I have just purchased a 4dr sedan model T-- The title says 1921, the seller said it is a 1923 as that was the first year for the 4dr sedan. Does any one know what is correct ?

As far as I know '23 was the first year of the 4 dr. Before was the center door. I believe the stamped frame numbers didn't start till '26.
Does your car have a "low" rad or the high rad. I don't think that 4 dr's had the low rad but that would indicate early or late '23 production. It should also have some amount of alluminum body metal if it is a earlier 4 dr. After that you get into subtle details like the type of window winder. The front fenders changed shape too.
Hope this helps a little

Les,
I have not brought it home yet and I do not know if it is a high or low radiator. It does have aluminum body as I put a magnet on it. This will be my first T and I am 76 years of age and never drove one yet but I am accepting the challenge of it all.-- thanks
Joe

Joseph,

Bruce McCalley's book "The Model T Ford" has a lot on the Fordor. The early Fordors (introduced in Dec 1922 ref page 308) did have the low radiator and used all aluminum body panels. Later the cowl was changed for the higher hood/radiator. The early ones did not have the cowl vent. As the 1923 year model progressed the lower body panels were changed to steel but the upper panels remained aluminum (so if you checked the lower body panels with the magnet --- and it didn't stick -- either lots of bondo or an early 1923). If you checked the upper rear panel -- it remained aluminum at least through 1924.

Welcome -- have fun and be safe.

Hap Tucker 1915 Model T Touring cut off and made into a pickup truck and 1907 Model S Runabout, Sumter SC