My first ever tab here so might not be perfect but I've noticed no one else has had an attempt at this  
so here's how I play it. 

Capo on first threat, play with alternating base (bottom two strings like most Johnny Cash songs) 

Also when playing C alternate between having your ring finger 3rd threat from the A string to low E string.  
This is what Johnny was doing so watch his video if you don't understand. 

C 
Well Uncle Bill was my Mothers Brother,  
F            C 
tall lanky man 
C 
But somewhere back in Uncle Bill's life, he took to sniffing cocaine. 
C 
I'd find him out in the back yard,  
F                     C 
sitting against a tree. 
C 
His eyes bugged out in a cocaine stare, 
F                             C 
and his mind in a cocaine dream. 
C 
Well one fall day when Uncle Bill was  
F                   C 
having a cocaine fit, 
C                   G 
He said Louise this coke's no good 
F                              C 
and I've made up my mind to quit. 
C                            G 
Now you take this key and I'll go upstairs and  
F                    C 
then you lock the door, 
C                  G 
and Lord I swear I wont come down, 
F                             C 
till I don't want dope no more. 




[Refrão]
C                                G                     F                  C 
Well he stomped the floor and he beat the door and he moaned a mournful cry.  
C                          G                    F                   C 
When the last cocaine went through his brain we thought he'd surely die. 
C                                G                      F                 C 
He yelled and he cussed and he fell on the floor and we almost gave up hope 
C                   G                F                   C 
As long as I live I wont forget when Uncle Bill quit dope. 

C 
Well for the first few hours we heard not a sound,  
F                          C 
upstairs was quiet and still. 
C 
and then all of a sudden we heard a shriek of  
F                  C 
pain from Uncle Bill. 
C 
He bounced out of bed and across the room, 
F                       C 
I heard him break a chair. 
C 
And then another scream louder than the first as he  
F                           C 
ripped out a hunk of his hair. 
C 
My Mother kissed us all that night,  
F                         C 
as brother and I lay in bed.  
C 
We wondered if poor old Uncle Bill was  
F                    C 
dieing or already dead. 
C 
But all night long we listened to him as he 
F                      C 
raved pleaded and called. 
C 
and I swear I heard his finger nails tearing the 
F                 C 
paper off the walls. 



[Refrão]
C                                G                     F                  C 
Well he stomped the floor and he beat the door and he moaned a mournful cry.  
C                          G                    F                   C 
When the last cocaine went through his brain we thought he'd surely die. 
C                                G                      F                 C 
He yelled and he cussed and he fell on the floor and we almost gave up hope 
C                   G                F                   C 
As long as I live I wont forget when Uncle Bill quit dope. 

C 
After fourteen days and nights of hell, it  
F                  C 
grew quiet over head. 
C 
And I peered past mother, as she unlocked the door 
F                        C 
expecting to find him dead. 
C 
But to my surprise there was Uncle Bill, as 
F                     C  
shiny as a brand new dollar. 
C 
His hair was combed and his beard was gone,  
F                          C 
he'd grown two inches taller.  
C 
In his old blue suite and his patterned shoes, he was 
F                  C 
quite a sight to see.  
C 
The light was back in his deep blue eyes, he  
F                     C 
turned to mother and me.  
C 
He said Louise I've been through hell and I  
F                C 
nearly went insane.  
C 
But I finally beat the devils habit, I  
F                    C 
beat the demon cocaine.  



[Refrão]
C                                G                     F                  C 
Well he stomped the floor and he beat the door and he moaned a mournful cry.  
C                          G                    F                   C 
When the last cocaine went through his brain we thought he'd surely die. 
C                                G                      F                 C 
He screamed and he hollered and he fell on the floor and we almost gave up hope 
C                   G                F                   C 
As long as I live I wont forget when Uncle Bill quit dope.