225 valve adjustment

I just got done doing a valve adjustment on my 68 dart, befor i started it sounded like a deisel, i adjusted it to .010 for intake and .020 for exhaust i also hade to turn down the idle. after that it was real quiet. i drove it about 15 miles and after i stoped i noticed it was ticking again, still not as loud as it was before but is that a tryal and error process or are slant six just a noisy motor? this is my first slant six