Need a hand Decoding this 4 speed

Need a hand Decoding this 4 speed

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Alaskan_TA said
Sometime during the 1969 model year, the second boss was added. They were not drilled & tapped for bolt holes at first though.

Early preparations for the 1970 model year with the E-bodies on the horizon.

It actually looks like an a body transmission. But the numbers say it’s a B body? Here are a few more pictures.

Jake