946421 Replacement 74" Flathead piston kit. +.060"

When you’re rebuilding a classic 1200cc Side Valve engine, you need components that respect the original design while offering modern reliability. This MCS replacement piston kit is sold as a set and features cast aluminum OEM-style pistons specifically for 1937 to 1948 74-inch U model Flatheads. These are +.060" oversize, making them ideal for cylinders that need a fresh bore to restore compression. The kit comes complete with wrist pins, retainers, and the necessary piston rings to get the job done right. As with any vintage engine overhaul, it is vital that a knowledgeable mechanic verifies the suitability of these components with other internal parts and follows proper break-in procedures. These pistons, which replace part 946421, are a solid choice for keeping those old 3-5/16" bore Flatheads on the road.