All Power+Plus Manifolds are cast in high pressure steel dies rather than pour-in sand molds as used by all other manifold manufacturers. This type of tooling costs two or three times what conventional sand cast patterns cost, but the finished product is worth this additional expense. And because the cores (which form the internal ports and water passages) are mounted in steel instead of sand during the casting process, there is no chance of any core shifts, which sometimes go undetected in sand castings. Core shifts can cause misalignment between the ports and the heads, or even actual air or water leakage. That is one problem you will never have to worry about with Power+Plus. Each and every Power+Plus manifold is subjected to a very thorough pressure test that will detect any air or water leakage. We find any problems first so you don't have to go to the effort of installing your manifold only to find out that it leaks and has to be removed and returned to the manufacturer. Power+Plus Manifolds are manufactured in a modern factory which produces OE aluminum manifolds for several major Japanese and European auto makers, so you know the quality is there. That same OE level quality, can be found in every Power+Plus Intake Manifold.