8BA-6621 oil pump is the standard factory type for the Ford and Mercury flathead V8 engines (221 and 239 and 255 cubic inch). Pump is known as the short body type and has a built-in pressure regulator. Maximum pressure is 80 psi. Pump does not include the pickup tube assembly (sold separately). This is a USA made replacement pump designed for the 1949-53 flathead V8 blocks. If using this pump for the earlier flathead V8 engines, you will need to purchase the 8RT-6615 pickup tube assy, which allows this pump to be used in the early rear sump oil pans of the 1933-48 blocks.