JR, You didn't say which overdrive ratio for 5th gear you have. There are two 5th gear ratios .64 and .82 for the TKO600.
If you have the .82 the 4.10 rear gears would be my preference for street and strip.
If you have the .64 it would be a coin toss for me because in either case 1st gear has a ratio of 2.87.
I installed the TKO600 in my '56 Chevy DelRay with 3.70 posi and 27.5" tall tires. I went with the short throw Keisler. It made banging the gears alot of fun.
At 500HP and 3400LBS? Your car should run 115MPH. Assuming your car turns 6400RPM I am guessing for a 500HP SBC? With a 4.56 gear and 28" tall tire she will run 116MPH in 4th gear.
It will also run 70MPH at 2500RPM in 5th gear which ain't bad.
For suspension, if drag racing is most important, Cal tracs and split monos are great but handle terrible. If you want both handling and drag ability you need to look at a Chris Alston G Link which has ajustment for both handlling and drag setting and in between.
We do quite a few G Links if you want to explore this more.