ALTDEV ON CLB. OVERSHOT ALT WHEN DISCUSSING TKOF TECHNIQUE.

Narrative

AFTER DEPARTING MKC WE WERE INSTRUCTED BY TWR TO CONTACT DEP; WHO IN TURN GAVE US THE FOLLOWING; 'CLRED ON COURSE; MAINTAIN 4000 FT.' MY SIC; FO; WAS FLYING AT THE TIME AND I WAS OPERATING RADIOS. BOTH MY FO AND I UNDERSTOOD THAT WE WERE TO MAINTAIN 4000 FT; HOWEVER DUE TO DISTRACTIONS IN THE COCKPIT (MY FO AND I WERE DISCUSSING HIS TKOF TECHNIQUE); NEITHER ONE OF US REALIZED WE HAD PASSED 4000 FT UNTIL APCH ASKED OUR ALT. AT THAT TIME WE WERE PASSING 4500 FT. I IMMEDIATELY LOWERED THE NOSE AND RETURNED TO 4000 FT APPROX 30 SECONDS LATER. WE REACHED 4600 FT BEFORE WE REACTED AND STARTED OUR DSCNT BACK TO 4000 FT. RPTING TO APCH WE WERE LEVEL AT 4000 FT; NO FURTHER COM ABOUT OUR DEV WAS RELAYED BTWN ATC AND US. I DO NOT BELIEVE THAT OUR DEV CREATED ANY CONFLICT WITH OTHER TFC. I BELIEVE IN THE FUTURE; I WILL ADHERE TO THE POLICY OF A STERILE COCKPIT DURING CLBS; DSCNTS; TKOFS; APCHS AND LNDGS. THIS DEV COULD HAVE BEEN AVOIDED HAD WE NOT BEEN DISTRACTED BY OUR CONVERSATION WHICH REALLY WAS NOT AN IMPORTANT ISSUE AT THAT TIME AND COULD HAVE BEEN DISCUSSED LATER.