Does Block Need to Be Resurfaced?

Cylinder heads and blocks may need to be resurfaced to restore flatness or to improve the surface finish, or milled to change the deck height for a variety of reasons. The deck surface on the head or block may need to be resurfaced if the surface isn't smooth or flat.

Is it necessary to resurface a cylinder head?

Cylinder heads may need to be resurfaced; to restore flatness or to just improve the current surface finish. A cylinder head may need to be resurfaced; after welds or other repairs have been made; or milled to increase the compression ratio.

How flat should an engine block be?

The maximum acceptable limit for out-of-flat on the deck surface of a cylinder head or engine block will vary with the application and type of gasket. For a pushrod engine with cast iron heads, out-of-flat should generally be . 003 in. ... Aluminum heads and performance applications should be even flatter – no more than .