I came across this calculator this morning and I like that it has side by side comparisons
Gear Ratio Calculator
I put the 46 on one side and the 8hp on the other. Since 3rd on 46 and 6th on the 8 are 1:1, I can look at those columns and know thats what my 904 will be at...
Talking with a few guys with Hemi swaps and 3 speeds and they like their 3.23 (3.27 Ford). Other future factors to consider tho