There is a decent chance you could find a stronger Bulbasaur than that if they're at all common for you but 405 definitely isn't a bad level to evolve something at. Basically unless you're desperate to have an Ivysaur right now then there's no real need to evolve the Bulbasaur until you have 125 candy saved up (enough to evolve it straight into Venusaur) and by that time you'll almost certainly have found a stronger Bulbasaur to start from. I generally save up to have enough candy for both evolutions with something like this but again, it depends on how much you want that Ivysaur haha. And for the Venusaur's CP I'd imagine around 1,400-1,700 for that which is pretty good but not too crazy for the candy it'd need.