Markings on converter

From what I have read there are only 3 converters used mid 60s to mid 70s. 10.75" and 11.75" for a 727 and a 10.75" for a 904. Hemis got a slightly different 10.75" with bigger threads in the drive lugs but other then that the same converter that a 318/727 used. All the different stall speed came from the power input. I'm not positive on the slant 6 but I bet if it's a 10.75" it's the same as the one from my 318 the factory service manual says the /6 stall is 1450-1650 while the 318 is 1750-1950. The only way to get a low buck higher stall is if you have a 11.75" converter and you swap it for a 10.75". One reason a 70 383 4 bbl ran so strong is it got the 10.75 while the 440-4 got the 11.75 so the 383 stalls 300 rpm higher then the 440. Put the 10.75 converter behind the 440 and it will stall as high or higher then the Hemi, or almost 600 rpm more then it did stock.