Sentence:  ... and he panted like a young faan in her fust race with the hounds, for he was <WSD>overtalkin</WSD>' his strength, and I feered he would die for sartin ef he didn't fetch up a bit and git rested; ... 
Meaning of the word marked with <WSD> tags:  To overstate; overexaggerate; talk up to seem greater than what is actual.