Can I Use Ford 351C Heads on a Ford 302?
The short answer to the question of using Ford 351C heads on a 302 block is yes, it can be done. In fact, Ford did this when they built the Boss 302 in 1969. Replacing the stock 302 head with the Cleveland head requires some special parts and a bit of light machine shop work, but the end result is an engine that is quite reliable and produces a lot of power.
Parts required for a 351C head swap
Bolting 351C heads on a 302 engine block results in a deeper and wider valley between the heads, which means the 302 manifold will not fit with the new heads. The manifold from an original Boss 302 will fit, but these are very rare and have become very expensive. Aftermarket manifolds for this swap were made by B&A Manifolds, an aftermarket supplier, who no longer makes them. Those manifolds have also become hard to find and expensive. A more affordable option is made by Edelbrock, which apparently saw a market for these manifolds and started making them in 2007, ensuring that finding a manifold to complete this performance modification isn't too difficult. This company makes manifolds to fit either a 302-based engine build or a 351W -based build.
Consideration must be given to the type of performance you are looking for. Engines planned for high RPM operation will benefit from using four-barrel heads, while more streetable engines will be produced using two barrel heads. In this type of driving, four-barrel heads would not be a good choice. Plan carefully before purchasing the 351C heads for your engine.
Ford's SVO department has the special head gaskets for this swap. Ask your Ford parts department obtain them.
Manifold gaskets are also needed. Edelbrock also produces the special gaskets for this swap. Stock Boss 302 gaskets work on heads designed for use with a four-barrel carburetor setup, and stock 351C gaskets will work with two-barrel heads once a hole is placed in them for coolant flow.
Swapping pistons is required because the location and angle of the valves in these heads is not compatible with the stock 302 piston. Several companies make pistons suitable for this use.
Some machining necessary
Coolant passages need to be drilled in the 351C head to match the manifold, and the stock coolant hole on the face of the head must be blocked.
Additionally there are holes that must be drilled in the 302 block, but the SVO headgasket can be used as a template.
These modifications are not major and should take little time or money to accomplish.
