Where is a good place to find out about the operation of a GM EGR valve ?
relative openong rpms, when the exhaust valve opens etc...
BTW its would be a 77 305 2gv

do a search on google for "77 305 EGR". personally, i'd just remove the egr, use block off plates on the ports and cap the vaccume line. you dont really need it anyways. think about it.... why would you want already burnt up and heated exhaust gasses entering your intake system? unless you have a newer model EGR thats eletronically controled you dont need it. oh and if you live somewhere where they have E Check.