Computers were pretty well accepted in the American mainstream by the late 1980s, but the designers that GM had making their ECU cases appear to have gone with the 1956-vintage E-13B font in order to enhance futuristic appeal.

That's right, folks, the engine in your 1989 GMC van is controlled by— gasp— a computer! Here we see Rambler Marlin racer Cadillac Bob displaying the replacement ECU for his 454. Computer!