I done it with them in the car myself,but if you yank it thats a good time to install t-chain,clean,paint,regasket it as well

2 1/2 foot of rope in each cyl,hand crank it up tight to hold the valves up,hand spring compreser,use the plastic sleeve and replace all the seals 1 at a time

if one is leaking the rest are not far behind,most will be cracked,broken and falling off if never been change from stock

do a comp check first and see if it needs a valve job and if now is the time for the heads to come off,if its good then R&R of the valve seals will go a long way for it till it needs a valve job