What year Poly? Early (up to 1966) the input shaft on the transmission had 19 splines, and the converters were a 12" NOT a 11". In 1967 they changed to a 24 spline input shaft, and my catalog still shows a 12" converter for the early 440 engine. You might also want to check on the diameter of the converters pilot, and make sure it's the same size as the bore in the crank.
According to my replacement converter catalog, it made NO difference what engine, except the hemi and the max wedge, was in front of a 727 up to 1966, converters were all the same, and were rated as a medium stall unit. I doubt that you'll get much more than 21-2200 rpm out of a factory 12" unit.