A rigid piston rocks less in the cylinder bore and improves ring seal. These T-6 heat treated pistons also offer reduced thermal expansion which allows you to run tighter clearances and allows the piston rings to seal better and minimize blow. These KB pistons have a single trench valve relief.
4.000" pistons are available in .030, .040 and .060 oversize.
4.125" pistons are available in .030 and .040 oversize.