The Precision RaceworksPhenolic Spaceris made in the USA from premium fiber impregnated phenolic material. With a Rockwell Hardness of 100 and a conductivity rating of 2.03 it is the perfect material for insulating between heat generating parts such as the cylinder head and other parts you wish to stay cool like the intake manifold.
Our 1/2" phenolic spacer not only provides a thermal insulation between the cylinder head and intake plenum. It has also been designed to make use of factory O-Rings rather than messy gasket maker adhesive to ensure an air tight seal each and every time along with easy installation and removal.
A phenolic spacer works by reducing heat transfer from the cylinder head to the manifold which results in reduction of intake air temperature, allowing for cooler air to enter the cylinders which is more dense and reduces chance of detonation in the cylinder.
This spacer is a must for all metal performance manifolds on the marketand works without stud extensions for many of the performance manifolds including all BMP intake manifolds.