You probably don't have close to 60lbs of muscle on your body...much less to gain anywhere close to that much. Most of your body weight is water, bone and teeth, organs/intestines and then muscle and fat. Most muscle is water weight...like 70% or so. So, not possible at 120lbs to gain 60 lbs muscle. Or 150lbs to gain 50 lbs muscle
come on man... nobody breaks weight or muscle gain down like that... people say " i put on 20lbs with this cycle".. never would they say i put on 15lbs of water and 5-6 lbs of meat.. plus if he was 120 with his natural level of hydration etc.. and he's 180 now ... i'm counting that as 60lbs gained...
getting a little too technical there matty...i think... regardless. a 60lb weight gain at a low bodyfat... i doubt many on here can say they put on 60lbs over the course of their training career .. and remained lean. a very impressive feat!
also why i said i couldn't give much advice on how to keep gaining as i haven't reached what TK has (60lb gain)... so if there is someone on here that has put on that kind of meat without a lot of it being fat.. then their insight on how to keep gaining after would be more valuable than mine. because if i knew how to do it..i would have already done it myself...lol