Visual Clues (often require some engine knowledge):
* Valve Cover Shape and Branding: Ford and Chevy valve covers have distinct shapes and often have prominent branding (Ford lettering or the bowtie Chevrolet logo) cast into them. However, aftermarket valve covers can obscure this.
* Intake Manifold: The shape and design of the intake manifold can differ significantly between Ford and Chevy engines. This is a more nuanced visual cue requiring familiarity with engine designs.
* Oil Pan: The shape and design of the oil pan can also vary between brands. Again, this requires some familiarity with different engine families.
* Distributor (older engines): If the engine is older and still uses a distributor, the location and design can be a helpful clue, though not universally reliable.
* Engine Block Casting Numbers: These numbers, usually found on a prominent part of the engine block, are the most definitive way to identify the manufacturer and specific engine model. You'll need a reference guide or online database to decipher them.
Things that are *not* reliable indicators:
* General size and shape: Many engine families from both manufacturers overlap in size and overall appearance.
* Color: Engine paint color is not a reliable indicator; it can vary greatly due to age, repaint, etc.
In short: The most reliable method is to find the casting numbers on the engine block and use an online database or reference manual to identify the manufacturer and specific engine. Visual clues can be helpful *if you're familiar with engine designs*, but should not be relied upon alone for accurate identification.
