Log Style Manifold for Mercruiser GM small block V8 on for the Starboard side, and was used up to 1982.
This manifold uses an Osco # O6351
90° down angle for most sterndrives, and an Osco # 6771
0° down angle for most inboard applications.
They made two manifolds that look very similar but the riser mounting pads are different, the riser pad on this manifold is 3-3/4 x 4 Inches.
Replaces Mercury Quicksilver # B-77235A2, 77235B
GLM # 51238
Sierra # 18-1951-1
Mallory # 9-40504 Barr Manifolds and Risers come with a 3-year limited warranty (PDF)!