What size are the freeze plugs on a Chevy 350?

There isn't one single size for freeze plugs (also called core plugs) on a Chevy 350 small-block engine. Different sizes are used in different locations within the engine block. You'll need to identify the specific location of the freeze plug you need to replace to determine its size. You can then either:

* Measure the existing freeze plug: This is the most reliable method. Use calipers to measure the outside diameter.

* Consult a parts catalog: A parts catalog specific to your engine year and model will list the sizes for each freeze plug location. AutoZone, Advance Auto Parts, Napa, and similar stores often have online catalogs you can search using your engine details.

* Take the old freeze plug to an auto parts store: A parts professional can usually match it to the correct replacement.

Don't rely solely on general information found online, as variations exist across different years and even slight casting variations within the same year of Chevy 350 blocks. Always measure or use a reliable parts catalog to ensure a proper fit.