Anybody know Saginaw 3 spds?

[mikiesride]

New man here.
I just bought a Parts lot sale of trans parts and the trans is one I have never seen before. Has a 5th top mounting hole or ear at the bellhousing to trans area, this one is a first for me. What is it, Specs below.

1. Bellhousing- GM7 3815891 (K15) 4.11/16" has two lower pad mounts,one hole one index pin each pad.
2. Main Case-GM24 6273245 (L33), top 5th mounting hole or ear. Stamping # C4Z140469 maybe partial Vin.
3. Side Cover-GM 3952645 (L193) 25, 7 bolt cover with one center top. below cover rt. lower side stamping-S4A19.
4. Tail Housing-326558 GM56 (A84).
5. Brg Retainer-GM27 3920740
6. Input Shaft- no groves, 1.18" dia.
7. Below the 2-3 shift lever (forward one) has a TCS switch.
8. Splines- 10 front. 27 rear.
9. Tail housing has a trans/cross member mount along with end of trans has 3 tapped floor shift mounting holes.

Yes I have did the Google thing with mixed answers, can any one help me with this for a RPO code or its line build #'s and or its common name?

Thanks in advance.

 

[mikiesride]

I did go to another Forum Site which was (6066gmcclub.com) and was reading some of there threads/post in the transmission section and did come across a conversation about this 5th hole mount trans, they said that GM calls it a "SM326 or just 326. I guess there site members are more into or more informed in 3 spd trans then here only because the cars & trucks back then used more of them then what is being used today, oh well at least I got my answer to what I was looking for.