Gear Ratio
For the 4th gen F-bods,3.23 and 3.42 were the factory gears with 3.73 being the popular mod for the automatics. 3.23s' or 3.42s' for your weight would be nice. Don't know what ratios are available for a 77 regal rear end,I believe it uses the 8.5" rear end.
Torque convertor-Yank SS3600 or CircleD equivalent.
Thats a heavy car, but my ws6 got 23 mpg on the freeway with 3.23 gears going 73mph for 2 hours.
I city drive it more vs freeway, so you just gotta decide what you do more of and put that gear ratio to use.
also how tall are you tires, it’ll make a difference on your gear ratio.





