John,
I have roller rockers and Felpro makes a laminated extra thick valve cover gasket thet works great with the regular Cobra valve covers. I never even had to mess with the baffels and I have been running these gaskets since 1997. Once in a while I will pull a valve cover and check inside and never a mark. I also got the 1" spacers but they made the covers sit to high and I never put them on. They did have 1/2 inch spacers at Cobra Restorers a year or so ago but I never bothered to get any as the gaskets work great. As for noise, I really can't tell you if the spacers would cause that or not. If you would like to try the Felpro route let me know and I will get the number for you. I always keep an extra set in the garage just in case I should get an
oil leak around one of the covers.
Ron
