I believe this head is for a 1 3/4HP Associated Or United engine, please research and measure up your engine before purchasing!! The 4 mounting holes that hold the head onto the block measure 4 7/8″ x 4 7/8″ across from each other on center. The exhaust threads are 1″ The pushrod holder bolt spacing is 1 3/4″ apart on center. The carburetor mounting hole spacing is 2 1/8 apart on centers. Valves appear to be new to the head. I do not see any breaks or welds. Please see pictures for the absolute best description. This item is old, used, and is over 100 years old.