I need an experienced opinion on whether to use Hylomar Universal Blue or Gasgacinch to seal the valve cover gaskets on a 440 Chrysler engine. Heads are aluminum Eelbrock performer and I will be using cast aluminum valve covers. I'm planning on using a Fel-Pro rubber "Fel-Co-Prene" VS 13379 R valve cover gaskets. I also have some Fel-Pro Cork valve cover gaskets on the shelf.

I have both Hylomar Universal blue and Gasgacinch on my shelf, but have never used either for valve covers. I have used Hylomar on a thermostat housing gasket which worked great. I have heard good things about Hylomar and Gasgacinch so I bought both, but wonder if one works better than the other for my application. I do not want to use any RTV sealant such as Permatex Ultra Grey, as it did not work previously, still leaked oil between the gasket and the head, eventually dripping oil out on to the headers. Engine has a solid lifter cam, so the valve lash needs to be checked occasionally. I also hate removing the residual RTV from the heads and valve covers.

Leak free valve covers is my goal. Thanks!