Here's what was available in 78 for Olds. Note the gear ratios for the 5 speed are different than the gear ratios listed in the service manual for some odd reason.
Thats a very interesting piece you posted. Thank you for posting it.
It is interesting to see that the Buick V6 was available with the 3 speed and the 5 speed, but not the 4 speed.
It is also interesting to see the 3 and 4 speed 1st gear ratios as 3.11 on both of them. On the Chevrolets, they were 3.50 for the 3 speed and 2.85 for the 4 speed. This I can attest I have 3 factory 4 speed gear boxes and 1 3 speed.
But it is interesting to see that each division was still doing things slightly different from each other.