3.09 gear set with 3.23's

You’ll need to play with some math.
First gear ratio of the current trans (2.66) times the rear axle ratio (3.23) equals 8.5918.
The current trans first gear ratio with the 2.66 starter gear and 3.91’s equals 10.4000
Now figure the feel good out of the hole ratio of 10.4000 divided by the 3.09 first gear to get 3.36 as a gear ratio. Since that’s in between normal Chrysler ratios, move up to the next nearest one.

Since Dan already stated 3.23’s will feel like 3.68’s, the 3.23 is to numerically low, step up to 3.55’s. 3.55 X 3.09 = 10.960 Very close. 10.960 - 10.400 = .056 difference. You can add the difference to the 3.91 to get the feel of the first gear ratio on take off.
3.91 + .056 = 3.966 Close to the 3.68.

If you liked the cruise rpm with the 3.23’s, it will only be a few hundred rpm higher with the 3.55’s. This is only a few miles an hour. Something you can ether slow down the car when driving to meet the old cruise rpm or step on the pedal for a few more rpm to meet the mph when driving down the road.

Ive made this exact rear gear swap between 3.23 & 3.55. It is a nice improvement but yet a very mello and minor one.