Natural GHR’s are pretty freakin hard. To remove any confusion for the readers, here’s a description:
-Get down on knees on a good, thick pad.
-Have a partner hold your ankles flat to the floor behind you, or wedge feet underneath a squat rack support or something.
-Lean forward as far as possible, without bending at the waist.
-Come back up (that’s the hard part).
If you can go all the way down without using your hands, that’s some good hamstring strength.
With that said, I don’t think 335 ATG squat is an imbalance with that hamstring strength. Seems about right to me, especially for sprinting. I think most people are imbalanced the other way, too much quad strength and not enough posterior chain. You don’t see great hamstrings near as much as you see great quads. I think stronger hams are much better, especially for your knee stability. I really think it contributes to much better ACL protection.
You don’t need to tip your workouts towards more quad work. Your fine. Maybe just change up excercises a bit to keep hitting the quads with new stimulus, but don’t worry about doing more quad work than ham work.