Which Intake manifold gasket

Absolutely, the exact same size is ideal. In practice with tolerances/gasket/intake shifting and with the flow hitting a right angle being very bad. I leave a very little margin. My guess is I’m running exactly that hour glass situation. The stock intake is gasket matched, but the runner tapers at the final bend in the intake. My cylinder head is ported and I have to assume the port ends up being bigger than the taper in the stock intake even with being gasket matched. I’m “building” an intake currently, that is such a shot in the dark due to me being a ham fisted monkey, no idea what I’m doing and the space constraints I have to live with. What could go wrong!