Chevrolet: cam shaft, cam shaft, jc whitney

Question
hi, i've got a 70 chevelle that has, what i believe to be a 350 in it.when idling, there's a constant ticking coming from the block. i had a family member, who's been a mechanic for over 30 yrs , look at it and he said the cam shaft is worn on #4 on the right side of the block. i know close to nothing about engine work. he's only in town for about 3 more days and he doesnt have time to do it for me. he explained how to tear the front end off so i dont have to pull the block out. do you think i should pay to have it replaced or take the advice of my grandfather in-law, who knows his stuff! i also have drums on the car in the front and rear and it would greatly be appreciated if you could explain how to change to a disc system.  

Answer
Brian;
Hi well as far as the cam it can be done w/o takling the motor out, at worse you might have to remove the grill. and with the brakes .I do not know why you would wish to change them, but you can look in (jc whitney.com) and they should have  a kit for it as you can find everything if you do a serch.