This is a quality seal/insulator hence my 3 star rating. 2101 intake manifold (transition from Edelbrock 1406 Carb to Edelbrock 2101 Intake). It leaves a huge air gap on both sides, it won't work in any way no matter what combination of pads you try, there just isn't any downforce material. Trust me, I'm a retired aircraft mechanic with 30 years of experience. One would think that Edelbrock thermal pad would be fully compatible with all Edelbrock products, but that is clearly not the case here. Sent it back and ordered a Edelbrock 8725 Gasket/Isolator instead which hopefully has a larger clamping range. Based on the reviews yes.