Help decoding 727

The closest I get to this is PK3640414 and is a 1973 318/360 727 truck, long, timing hole trans

Recheck your number
Yeah thats exactly what i got also when i decoded it but just wanted to be sure. I boight a 70 340 off a guy and he had that 727 behind it? Wanted to see if i can somehow find out the torque converter it came with? Im guessing the original tranny mist if went out i guess but unsure the guy didnt have any info on it other than they were mated together