So I beat the 8th gym with a level 40 Venusaur and now the rest of my team is 40. Is there a good grinding spot before Victory Road?
No.
No.
No.
Nope. You'll be better grinding at Victory Road.
I did it at B1F, if you have some pokémon with trouble beating Onix, Graveler, Golbat or Machoke I suggest you use the Exp. All with a strong lead + that pokémon in the party.
Oh and be careful about leaving some trainers available if you want to try some glitches to fill up your pokédex.
Thanks anons.