This is a Manifold for a Chrysler Big Block (383/440) from 1959 & up until a Center riser Was used. Osco Manifolds and Risers come with a 3-year warranty (PDF)!
This is a Manifold for a Chrysler Small Block (318/360). It is a log style and was used after 1965. It uses Manifold Mounting Kit OSC826MK. Osco Manifolds and Risers come with a 3-year warranty (PDF)!