compressed air method to change seals

hi, it can be done without air or rope. run piston to #1 tdc, remove springs, valve will drop 3/16 of an inch. piston stops it. also, can change # 6 same time. rotate 90 deg, do # 8 & # 5, rotate to #4, can do # 7 also. rotate # 3 can do #2 same time. I've changed valve springs this way many times. when you're at the races, you don't have air. # 1&6 , #8& 5, #4&7, #3&2. simple.