Dear Jim, Jim, and mid-60s Buick caregivers who enjoy some modern car touches,
So far I am loving the 200-4R in the 66 GS. The car seems to like it even with the 3.08 gears. The car is smooth and quiet and 70 MPH is about 2300 RPM. It sure is noticeable now when I drive one of the other Gran Sports.
I'll gladly second that motion! My Dad and I first discussed trying to get an overdrive transmission fitted to Biquette around 1980! Even on surface streets at over 35 mph, Biquette goes into overdrive and is that much quieter - just like a modern car. Obviously you are tinkering with the authentic 60s car driving experience, but you if want to make the car more pleasant to drive, an overdrive transmission will go a long way in achieving that.
Cheers, Edouard