I'd be surprised if you could process more than 400 cal/ hour while riding. That is something you will need to establish by trial and error. The athlete who can process 600 cal/hour is rare but real. You may be him.
I can't comment on the quality of what you are eating without knowing your Infinit blend or the granola bar ingredients. Mostly carbs is what you need.
Your last comment is key – make sure your glycogen muscle and liver stores are topped up prior to long rides.
I'd recommend trial and error…eat different things on your ride. Cut back the energy drink to 200 cal/hour and take in solids or semi-solids in small frequent portions. Try foods with a lower sugar content and more complex carbs. Add in a small amount of fat and protein.
Calorie timing? Did you eat the 2 granola bars at one time? 400 cal of sugar going down the hatch in a small time frame can lead to a blood sugar yo-yo and cause what I term a “sandwich bonk”. I get a sandwich bonk if I eat too many calories at once past the 3 hour mark of a ride. A sandwich bonk is as you describe – tunnel vision, spacey light head. More sugar on top of a sandwich bonk makes it worse. You just have to wait it out and let your body stabilize its blood sugar. For me this takes about 8 minutes to do. YMMV as you are clearly bigger than I (I am 105 lbs)
You have further detective work and experimenting in front of you.
Lynda