If it were a bolt or close to stock car....4.10s. 400hp or less.....4.10s with a tire worth two shits.
Its really gonna be all opinion. If you arnt gonna stick any type of forced induction on it and dont mind cruising on the freeway at 3k+ and do a lot of racing from a dig then >3.73. If no to any of those I would say 3.73 are perfect. I have 3.90 and most of the racing I do is on the freeway and I dont like keeping up with traffic being at 3200rpms constantly in 5th gear. Im switching to 3.73s they just seem perfect from the ones I have driven and ridden in.