Store › Lower Gasket for Adapter Plates Lower Gasket for Adapter Plates $13.50 .060” Fiber gasket used for 5.7, 6.1, & 6.4 adapter plate conversions. Gasket mates the cylinder head to the adapter plate. .060” Fiber gasket used for 5.7, 6.1, & 6.4 adapter plate conversions. Gasket mates the cylinder head to the adapter plate. Quantity: Add To Cart Added!