ACDelco 9746BB Spark Plug Wire Kit : Amazon.com : Automotive

vs. ...

ACDelco 746BB Spark Plug Wire Kit : Amazon.com : Automotive

And let me be the first to say "$16.44.", ... Clearly there is something(s) else.

A lower-quality set perhaps?

A set intended for the L36, & one for the 67 maybe?

 

I think so...
One is a premium set designed for l67 i think.., on rock auto they sell the same two wires I believe. One is basic, the other is premium stock.

 

In 'old school' terms the less expensive set is a 'suppression set'. It has a stainless steel core wrapped with fibers. The more expensive one is a 'solid core set'. They have a solid copper core wrapped in fiber. They won't suppress RF interference as well as the stainless core, but offer less resistance so they transfer energy better. Other differences are the thickness and quality of the jackets and boots - the more expensive wires having the better quality.