Firstly, Groudon has its own deck and actually placed second at Florida Regionals just a week ago. The pilot was also my brother, with a list that we've been brainstorming since Groudon's printing, so Groudon is already pretty fearsome.
But to your list, I think there's a far easier option if you want to go the acceleration route. Have you considered Landorus from Furious Fists? This card, for one Fighting Energy, deals 20 damage and accelerates a Basic Energy from your Discard Pile onto one of your benched Pokemon. It's pretty much what Garchomp does, but on a Basic. Now, I realize you want to pile on a bunch of Strong Energy on a Groudon, but wouldn't it just be easier to attach them from your hand straight up, whilst quickly powering up a Groudon with a Landorus? I mean, in my experience, you typically only need about one Strong anyway.
Another thing I noticed is you don't play Focus Sash. Focus Sash is an incredible item in Groudon decks because your opponent cannot remove it with a Xerosic or a Startling Megaphone -- they pretty much have to hit you to your Sash. In other words, you have two free attacks with Groudon. One when you come active, and one after the Sash was hit. But even better, you can Focus Sash your Landorus to where they can survive yet another turn to power up your Groudon. Now, since you need to attack and Primal in the same turn, you will have to use the Spirit Link, taking up Focus Sash's slot. What I used to remedy this when I played what we're talking about was Tool Retriever. This also allowed me to remove Head Ringer.
Now, with all that being said, here are the changes I would make to your list:
-3 Garchomp //Reasons stated above
-3 Gible
-3 Rare Candy //No need without the Stage 2
-2 Judge //You'll see in a minute!
Subtotal: -11 cards, 49 cards in deck
+4 Landorus //Reasons stated above
+2 Professor Sycamore //Not only does it draw you a bucket load of cards, but it also discards Energy that you can attach with Landorus and Mega Turbo. This was Judge.
+3 Focus Sash //Reasons stated above
+2 Tool Retriever //Reasons stated above
Those are the changes I'd make. Although, I also might play another Switch. Starting Groudon is literally the worst thing ever unless the matchup is, like, Sableye.