The early HiPo (High Performance) engines were first offered as an option in June, 1964. Early HiPo engines had a 5 bell housing bolt engine block. Some of the other characteristics that set this engine apart include the following:
- Solid lifters and flat tappet camshaft.
- Autolite 4100 4V 1.12 Venturi carburetor with a manual choke. Some K Code engines used a Holley carburetor with a list number of “3259” (these Holley carburetors were often used in Mustang Shelbys) .
- Cast iron header type exhaust manifolds.
- Autolite dual point distributor (later HiPo 289 engines used FoMoCo or Motorcraft dual point distributors).
- Cylinder heads had screw-in style rocker arm studs and a recessed pocket for the valve springs. All of the cylinder heads had a “19”, “20”, or “21” casting number on the front or rear ear of the head.
- Heavy duty connecting rods (these were the same as the ones that were later used in the Boss 302 engine).
- Larger diameter alternator pulley.
Mustang 289 HiPo K Code engine production was discontinued after 1967. The 1968 Mustang J Code 302 4V engine took its place.