Holley Brass Idle Mixture Screws & O-Ring Gaskets. 

These new idle mixture screws are compatible with alcohol, methanol  and E-85 gasoline.  Used on Holley/Mustang 4180 4 barrel carbs where idle mixture screws are attached to the base plate. 

You will receive TWO screws & O-Ring gaskets. 

Screw head needs a 3/32" Allen wrench.

Please contact me if you have any questions about fitment.