ok... my 91 z28 w/ 305 doesn't have an oil filler cap. I went and got the stock on and it is way too small. After trying to find the right one I realized the valve cover hole doesn't even have threads on it. Is there supposed to be some kind of gasket you put in first or something?

 

hm, i think the threads are supposed to be part of the cover. do you have aftermarket covers or factory?

 

I'm pretty sure they are stock valve covers. They don't look like aftermarket