I'm 6'4" also.
If my knees are together and my feet are just on the floor in front of my seat - the person in front of me won't be able to recline - at least not very far. They'll hit my knees ever time.
Now - if I can slide my feet under the seat in front of me a little (depending on if I have to have a carry on there) then this doesn't happen. Or if I have a moment to spread my knees a little, it doesn't happen.
But in all honesty - if I'm just sitting in the airline seat with my knees together and my feet on the floor right in front of me (not stretched what little I can under the seat in front of me) there is no way they'll be able to recline the seat in most airlines I've flown on.