1975 Plymouth Duster Slant Six 255 Oil Cap
 

What kind of oil cap does this engine require?
It says to use this but the original one looked like the second link.
http://www.ebay.com/itm/Stant-SO75-C...0AAOSwo4pYZrvf
http://www.ebay.com/itm/Engine-Oil-F...IAAOSwSzRZN~YZ

I meant 225 for engine size btw
Also if anyone knows the actual oil to use for this or has a website that tells you please link it.

depends on if yours has a hose that goes to the air cleaner which it probably does or had..