This is a replacement shaft and drive diamond assembly for both Vertex and Joe Hunt Chevy bases. The shaft can become damaged due to the engine stopping abruptly and twisting the oil pump tang on the bottom. The shaft can also be bent when the magneto takes a hard blow, such as when a car flips over. Shaft must be drilled once installed to ensure the proper .005” clearance between gear and base. Please select the application when ordering your assembly.

Note: Select the steel drive diamond if your magneto has advance and aluminum if the magneto is locked out at zero degrees.