can anyone give me an approximate ET on a valve cover gasket job for my 89 i know its hard to tell cuz things can go wrong but im just looking for an approximation and also while i have it stripped down that far should i just keep going and do the headgaskets at the same time or just wait till they go? also any advice on the bbbbest quality gaskets to use cuz i really want to avoid repetitive tear downs as much as possible? thanks for any input on the matter