Garchomp has no synergy with Porygon-Z.
Both need many different types of basic energy, but this doesn't mean that they do well together.
They also can be countered in one strike. Battle Frontier hurts both Garchomp and Porygon-Z, as well as anything that cancels weakness.
Porygon needs energy recovery that works with all types of energy (Magneton, Plusle).
Garchomp needs energy acceleration (Togekiss, Weavile).
So you want to play a deck with Garchomp, Porygon, Togekiss and maybe even Magneton?