Do you have to change the head gasket when replacing a camshaft?

In most cases, yes, you will need to replace the head gasket when replacing the camshaft. This is because the head gasket helps to seal the joint between the cylinder head and the engine block, and removing the camshaft will disturb this seal. Additionally, the head gasket may be damaged during the removal and installation of the camshaft. For these reasons, it is generally recommended to replace the head gasket when replacing the camshaft.