How do you tell the difference between an Overdrive 4 speed manual Transmission, (mopar) and a regular 4 speed?

Mopar made an A833 Transmission., one was 1:1 straight thru in 4th , the other was an overdrive that was 1.25 to 1 in 4th ., the latter was used behing the slant 6 and was not very strong, the other one was strong and used behind the 440 cu in engine., How do you tell the difference from the outside., of these two A833 trannys.??|||1.25:1 is not an overdrive gear. An overdrive gear is something like .86:1. I doubt these two trannies have the same bell housing if one is used for a big block and the other is used for a slant six. The bell housing should determine which one is which.