So we can conclude that Vikavolt has at least base 75 HP, possibly more if its HP IV is less than 31.
For comparison, here's the base HP for all fully-evolved, early-game Bugs in earlier generations. Total BST (disregarding Gen VI changes) in brackets:
Butterfree: 60 (385)
Beedrill: 65 (385)
Ledian: 55 (390)
Ariados: 70 (390)
Beautifly: 60 (385)
Dustox: 60 (385)
Kricketune: 77 (384)
Leavanny: 75 (490)
Scolipede: 60 (475)
Vivillon: 80 (411)
The "early evolvers" all seem to have fairly low HP, which fits well with their low overall stats and BST. The exceptions are Vivillon, whose stats appear to be "tailored" for better perfomance (comparatively high HP, Sp. Atk and Speed, crap everything else, and a BST much higher than other early bloomers, to boot), and Kricketune, which just seems to focus on HP and Attack overall, the rest of its stats being thoroughly crummy.
Leavanny and Scolipede are both "late bloomers", reaching their final form after high Friendship (no earlier than level 21) and level 30, respectively. They also have a much higher BST than the other early-game bugs. Vikavolt was seen evolving at level 28 in a trailer, comfortably following the former two in their tracks.
The conclusion seems to be that Vikavolt is either tuned for a fairly defensive build (which is unlikely with that design, and Electric types don't tend to have high HP), or that it will follow its "late bloomer" cousins and have a fairly high BST for an early-game Bug. The high HP stat just follows the rest of the BST, and it's possible that Vikavolt will excel in other stats as well. Scolipede and Leavanny both have offensive stats above 100, and decent Speed too: 92 for Leavanny, 112 for Scolipede.
From experience we can then expect Vikavolt to have a BST around 480-500, with at least two stats at or around the 100 mark, the rest being around 70, give or take 20. Not a game breaker by BST alone, but given the right moves it should be a solid choice for an in-game team.