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_BwEI 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