With a straight edge and feeler gauges.
The intake & exhaust manifold must be removed, then the head is remove. Head inspected for cracks and warpage, all gaskets replaced and all parts reinstalled.
Warpage in an aluminum cylinder head is typically caused by overheating, which can lead to thermal expansion and subsequent distortion of the material. This can occur due to prolonged high engine temperatures, inadequate cooling, or a failed head gasket. Additionally, improper torque specifications during installation can contribute to uneven stress distribution, resulting in warping. Regular maintenance and monitoring can help prevent these issues.
The stroke is simply the distance that the piston can travel up & down in the cylinder. If you have the cylinder head off, or access to the crank it's quite easy to measure.
If it is running out between the block and the head, you probably blew a head gasket. If that is the case, be sure and have the cylinder head resurfaced before you re-install it after you change out the gasket. A blown head gasket is usually caused by warpage of the head when it overheats. TIP: as long as the head is going to be resurfaced, you might also get the valves reground.
You would change the head gasket. You would also have the head checked for cracks and warpage. You would also change the engine oil and filter.
Remove the intake & exhaust manifold. Then remove the head. Have the head inspected for cracks & warpage. Reinstall everything with new gaskets.
No
The cylinder head is located on top of the engine. The spark plugs thread into the cylinder head(s).....
Cracks can be welded and then the head can be resurfaced.
Take off a cylinder head and measure the diameter of the bore.
Heads must be removed, inspected for warpage and cracks, and new gaskets installed.
A 402, is a 396, .030 over. With a thinner cylinder wall, it will heat up a little faster, and higher. Cylinder head warpage occurs around 230, or 240. Your motor should never run this hot on a consistant basis. 180, to 200 degrees should be the normal operating temp.