There is where the physical similarities begins. Triple H obviously was heavily influenced by Race. From the flying Harley Race knee, to the Harley Race beard, Triple H tried to emulate that man to a T. Emulating Harley Race is a great move by Triple H, because Harley Race is arguably one of the top 5 wrestlers of all time.
People need tor ealize what Harley Race and his multiple Title Reigns means. Harley became the face of the NWA in the 70's, and carried the title most of the decade. While the same could be said for Triple H and the 00's in the WWE. They have very similar careers. Both were pretty damn good heels. The whole Harley being able to cause riots speaks to the difference of the times though. Fans now are a bit more tranquil in their approach to things. Vocal yes, but physically violent, very rarely in wrestling do you see it now a days.
My dad says that Harley Race is the best wrestler ever, I tend to take his word pretty strongly considering he's the man that introduced me to the business. I am not Triple H's biggest fan, but I don't think he matches up. Triple H has the advantage of having the full backing of the WWE marketing machine, Harley mastered the territories.
Plus, Harley clearly handed the torch off to ric Flair, who became the clear head of the NWA after that. Triple H, I know it's debatable, has yet to show that he can hand the torch to someone without grasping it back.
*Edit: The bottomline is, if you are a Triple H fan especially, you really owe it to yourself to watch Harley Race matches if you get the chance. They may be long and in a style your unfamiliar with, but the man was truly a master of his craft.