NOS 1955–1980 GM Chevrolet NYLEN QUALITY 14221-M STD Main Bearing Set

Description:

The below information was provided via an "AI" search - cross reference part numbers and look at pictures for verification - I have no idea except what an internet search provided - if you are not 100% certain this is the item you need - do not buy - sold as is where is - no returns.

🔧 Part Overview: NYLEN QUALITY 14221-M STD Main Bearing Set

This is a New Old Stock (NOS) main bearing set  part number 14221-M STD. The “STD” suffix indicates standard size, meaning it’s designed for crankshafts that haven’t been machined undersize. The packaging and bearing style suggest mid-century production, likely from the 1960s–1970s.

🛠️ Application & Fitment

While Ohio catalogs are limited, the part number 14221-M STD aligns with listings for:

• Chevrolet small-block V8 engines, including:

  • 283, 305, 327, 350, and 400 CID

  • Used in 1955–1980 GM passenger cars and light trucks

• Equivalent to aftermarket references like Federal Mogul 14221M STD

These bearings support the crankshaft within the engine block and are critical for maintaining oil clearance and rotational stability. One listing noted the application as “unknown”, which is common for obscure NOS parts, but the part number structure and bearing dimensions suggest compatibility with Gen I Chevy small-blocks.