CO-OP E4 Row Crop Tractor
I think this is an E4. Made from 1949–1958, it was basically the same tractor as the Cockshutt 40.
From the Tractor Date website: 'The CO-OP brand of tractors was born out of a desire by farmers to reduce cost through collective ownership of machinery production. Early models were designed by Dent Parrett, formely of Parrett Tractor, and built in Michigan using a number of Chrysler components. In 1938, production moved to new facilities in Indiana. Cletrac also contributed a few models and some production occured in Saint Paul, Minnesota, at this time. After World War II, an arrangement with Cockshutt led to the new "E" series of CO-OP tractors which were simply re-branded Cockshutt models. Poor sales led to the CO-OP facilities being sold to Cockshutt in 1952, and the CO-OP brand was discontinued.'
Cockshutt themselves partnered with Oliver, who'd joined up with Hart-Parr and were all swallowed up by Case in the great consolidation of Tractor brands and manufacturers.