[32phil]

No one mentioned the shifted ratio of the Columbia
A 3:78 Columbia shifts to 2:78
A 4:11 Columbia shifts to 2:97
Either one gives a good Highway final rear gear when shifted.
The engine/trans combo and how you use the car without engaging the Columbia is the question.
Right now we have two cars with Columbia overdrives, one is using a mildly hopped up 21 stud V8 using the 4:11/2:97 combo.
The other is using a 55 Dodge Hemi, mildly hopped up, using the 3:78/2:73 combo.
Both cars have 1:1 final drive in the transmissions.
They are both currently under construction, I'll know more in the Spring.