I run these on my 432 Stroker with Edelbrock Heads

Not only do they protect the valve cover gaskets from heat they keep my valve covers looking brand new

I also had my factory exhaust manifolds planed at my machine shop before installing

https://www.summitracing.com/parts/fel-m...AyABEgKcvfD_BwE

I like the Remflex also , but if you ever have to remove the manifold or loosen for any reason the gasket will come apart as they stick after compressed

Do they work , Yes

A little more expensive , Yes

One time use , Yes