Plz Help with Trans Gearing

[Davidless]

Hi All
Another SF question so I’m looking for your opinions plz.
I need to order my trans and having a tough time with the overdrive gearing choice.
It’s a TKX 2.87-.68 or a 2.87- .81. Rear end is 3:45 (standard with a new roller).
427 sb with hp in the low 500’s

I’m running 18” wheels and a 110 LSA cam which I believe will need to run at 2200 rpm minimum. It’s mostly street driving with maybe some auto cross if I feel daring, not any track straights right now that I know of, maybe a yearly play day at the Glen but no racing.

So with that said if I use 2400 rpm as the bogie I’m looking at 90mph with a .68 OD 5th gear which is 32% over drive compared to a .81 which will cruse at 76mph 19% OD.

It’s hard to really get the feel without test driving to compare the difference.

Thanks for any thing I may be missing

David