* 350 ci is a measure of displacement in cubic inches, an older unit of measurement. This was a common displacement for small-block Chevrolet V8s.
* 5.3L is a measure of displacement in liters, a metric unit. GM's 5.3L V8 is a modern engine with different internal components and design compared to the older 350 ci small block. While the displacements are similar, the 5.3L is generally slightly smaller than 350ci (which equates to approximately 5.7L).
While they both represent a similar engine size and power output range, they have significant differences in design and technology. You can't just swap parts between them.
