Need gear ratio , tire and rear end ratio experts ! Green Rat Project

but dont foeget that i can go 14 15 16 17 even 18 inch in the back.
The wheel size means almost nothing.
In an A-body from 67 to 76, the maximum tire diameter that fits without mods, is ~27.5. And the smallest that anyone is likely to run is a 24.5
My numbers are always done with 27s, unless otherwise stated, because 27 is the average of just about anything you would install.
3.23s will run ~1900@65mph which is fine. But for best fuel economy, your engine will want perhaps 50/55 degrees of cruise timing. You cannot get that much with the factory-type Distributor.
Typically, you might get 35*
If you mod your Vacuum advance can to 22*, then ~43.
If you way over-advance your idle timing, which will make her super jumpy in gear, then perhaps 47.
That's all I'm saying.
I ran 3.23s with a .73overdrive once; but not for long
In your combo, that will have a starter of 12.98. But in Second gear, it is 7.49, and that would be a tuff starter to pull even in your combo. (That would be like running the Standard 2.66Low/A833 and 2.76s). Thus you are forced to use First gear every time you start off. But the engine will rev up really fast, sorta encouraging you to short shift into Second. But then the Rs will fall so low, (to 60%) that the engine will struggle in that 7.59 ratio
To run that deep with my 3.09First gear, requires 4.30s; Hyup I pulled and sold them. That starter was just too deep for me.