A53 small block transmission??

[Morris'_Mopars]

I was going through all my transmissions in my shop. Checking numbers and labeling all of them. I have a small block trans that is a A53 option. Im not sure if it is just another 727 or if its something special. Here are a couple pics...Anyone have any info??

[1 Wild R/T]

Used in late 70 340 applications including but not limited to AAR-T/A.... Also used in 340 A bodies & E bodies...