What tools are used to check for a warped cylinder head?

To check for a warped cylinder head, a straightedge and feeler gauge are commonly used. The straightedge is placed across the surface of the head, and any gaps between the straightedge and the head are measured with the feeler gauge to determine warpage. Additionally, a precision straight edge or a machinist's level can provide more accurate assessments. If significant warpage is detected, the head may require resurfacing or replacement.