the 420 is a great transmission with 2-3-4 synchronized, a big improvement on the earlier crashbox. As for your earlier question, I had a 327 with a later 420 behind it in my '63 c10. as far as I know it will work with any sbc with the correct bell housing. If I were messing with it anyway, today I'd opt for the t5 to get the overdrive ilo a 420.
