* 302: The 302 Windsor has smaller valve covers, generally more rounded and less prominent.
* 351: The 351 Windsor has larger, taller, and more rectangular valve covers. They're noticeably bigger than those on a 302.
While valve covers are the quickest visual clue, here are some other ways to tell them apart:
* Intake Manifold: The 351 intake manifold is significantly larger than the 302's.
* Engine Block Casting Numbers: These numbers are stamped on the engine block itself and definitively identify the engine. However, they require cleaning the area to read them clearly. You'll need a casting number chart to interpret these.
* Displacement: This is the most obvious difference, but requires checking engine specifications or documentation. The 302 is a 302 cubic inch engine, while the 351 is a 351 cubic inch engine. This information may be found on a tag on the engine, if still present.
In short, the valve cover size is the fastest and easiest visual method to tell the difference between a Windsor 302 and 351 engine.
