How can you tell from 305 and 350 motor?

You can't definitively tell the difference between a 305 and a 350 small-block Chevrolet engine just by looking at them externally. Both engines share a very similar overall design and many external components. To be sure, you need to check either the casting number on the block itself or the engine ID code (if present).

Here's why visual inspection is unreliable and what you *should* do:

* Similar Size and Shape: The 305 and 350 share the same basic block dimensions and external appearance. They use many of the same bolt patterns, accessory mounting points, and overall configuration.

* Casting Numbers: The engine block itself has a casting number. This number is unique to each engine and can be used to definitively identify it (including displacement). Look for this number, usually on the front passenger's side of the block. You'll need a GM casting number reference guide to decode it.

* Engine ID Code (VIN Tag): Sometimes (especially on newer vehicles), the engine ID code is stamped on a tag located on the engine. This code can provide the engine's specifications.

* Other Clues (Unreliable): Some people try to estimate based on things like carburetor size, intake manifold, or valve covers. However, these components are easily swapped and don't guarantee the engine's displacement.

In short: Do not attempt to identify the difference visually. Use the casting number or the engine ID code for definitive identification.