def changeText(elem):
    global checkDicktionary
    for key, replTxt in checkDicktionary:
        if elem == key:
            return replTxt
    return elem

#Ввод из Динамо закомментировал. В качестве примера - код
#elemList = IN[0]
#whatToReplace = IN[1]
#replaceText = IN[2]

#Ниже приведен пример. Заменить на нужное.
elemList = ["50","50","60","60","65","65","75","75","80","80"]
whatToReplace = ("50", "65", "80")
replaceText = ("57x1.5","76x2.8", "89x3.0")

checkDicktionary = zip(whatToReplace,replaceText)
outlist = list()

for elem in elemList:
    changedElem = changeText(elem)
    outlist.append(changedElem)

OUT = outlist