Take a closer lool, its probably not really ECT. Clean off the grease and grime and take another closer look. Also, look at the carburetor mounting bolt patern, is it square or rectangle in shape? That will give a better clue as to what year it is. The square pattern 4bbl intake was used in 54 Mercury( 256), and 55-56 Ford and Mercury on the 292 and 312 engines. The rectangular bolt pattern was only 1957 Ford 312, and some 58 59 60 Mercury's with the 312.