Overview Product Description RH. MLS. .0413" thickness. 4.173" O/S fire ring ID. Increased ID for bored blocks. Use new head bolts. Product Videos Custom Field Product Reviews Write a Review Write a Review × Engine Components Engine Cylinder Head Gasket - Kit Part - HC403R-OS Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name *Email *Review Subject *Comments