Need help ID this trans. 4 speed

[Adam123]

I got this 66 c10 truck and I need a new shifter for it but I don't know the what the trans is. This is all I have to go on.
Thanks for any help. I need the shifter and linkage that bolts to trans.

 

[cmkruse]

1964-80 GM Saginaw Cast Iron 4 Speed Manual Transmission 3925656 .