1954 Mercury Mark 50 powerheads. This is a combination of three blocks. One is complete, one is a block and crankshaft and one is a block. These are hard to find and one year powerheads only. The pistons and rods are compatible with some KG, Mark 40, Mark 55, Mark 20 and Mark 75 outboards. Appear to be fresh water use. We can ship via UPS. Shipping costs varies to location.