From memory without looking it up, there were about 27 AC-built 289 cars on the coil-spring chassis with the so-called 427 body. Again from memory, they were narrow-hipped, wore wire wheels, and at least some retained the chin scoop even though they didn't require
oil coolers. Remember that a number (perhaps fifty) of the Shelby 427 street cars omitted the scoop. At any rate, there does exist a historical precedent for a small block in a coil-spring chassis.
Sal was close on the name: "AC 289 Sports"