While not an expert on vintage tractors I would guess it is one of the last Ferguson tractors built in Detroit.
Harry Ferguson, an Anglo-Irishman, developed and patented the tractor Three Point Hitch. He licensed the Three Point Hitch and his tractor design to Henry Ford, who mass produced the Ford 9N (1939), 2N and 8N from Ferguson's design. Later Ford and Ferguson divorced. Ferguson then manufactured tractors, begining in October 1949, on his own in Detroit before selling to Massey-Harris in 1953, which soon changed its name from Massey-Harris to Massey-Ferguson.
The red 'Massey' paint is a clue. As is the swept around radiator body work. The gray paint is also a clue. It indicates tractor originated in the Detroit Ferguson factory. I am guessing (first) you have a late Ferguson F-40 or (second) one of the first Massey-Harris 50s, which shortly became the Massey-Ferguson 50. The transition tractors are a little difficult to identify. Certainly one of the best engineered, carefully built tractors of its day. Lucky find; tires are hardly worn.
LINKS (2):
TractorData.com Massey Ferguson F4 tractor information
TractorData.com Massey-Harris 5 tractor information
Check the fluids, drain the old gas and fuel with
non-ethanol, turn the engine by hand to make sure it is 'free'
before attempting to start. If it starts, drain and replace all the old fluids, change all the filters within 1/4 engine hour.
You will find more useful Ferguson information available on vintage tractor web sites than here.
LINK TO TBN ARCHIVE:
Google:TBN
This Ford tractor site has quite a bit of Ferguson information:
N Tractor Club
Amazon and e-Bay have books on Harry Ferguson and Ferguson tractors. Also, check e-Bay/U.K. books.