Agree with RoseCity427.
If your goal is better drivability in a 4000lb car like a Galaxie, you want a balance between SLR (starting line ratio) and cruise speed. In other words, you want the car to be able to move off the line well while at the same time, you want it to cruise at 65-70mph ideally turning 2500-2800 RPMS or less.
To do that, you need the right gearing. As RoseCity427 said, moving to a wide ratio transmission and 3.50 gears will accomplish that. Close ratio tranny's have a tall first gear and when mated with low rear gears (4.11, etc), they're fantastic at getting big beast Galaxies off the line at the strip. The downside is you lose cruise speed. In other words, you're taching 4000 RPMS at 65mph.
Switching the gearing will make all the difference. The wide ratio will have a higher first gear and when you mate that to a mid-3s axle, like a 3.50, you'll get the off the line gearing you need to move a big car out of the hole all the while you have the cruise speed at the top end.
Case in point: I converted my close ratio toploader to a wide ratio. Rear gears are 3.50. End result is my SLR is 9.73, a vast improvement over the stock 7.54 which is dismal for a '66 big-block car this size. Meanwhile, in addition to the car moving off the line much better now, I actually have better cruise speed. I'm turning turning about 2800 RPMS when cruising at 70mph.
Overall driveability has vastly improved. Hope that helps ...
Last edited by 66SevenLitre; 04-13-2019 at 02:45 PM.