The 7.3L Power Stroke was introduced in 1994 and continued through mid-2003, produced by International Navistar. This model is also known as the “OBS” which stands for “Old Body Style”. The 7.3L Power Stroke is an electronically controlled direct injection which uses a single shot HEUI (hydraulic/electronic unit Injector) fuel injector backed with a high pressure oil pump (HPOP). The 7.3 utilizes the HPOP in conjunction with a low pressure lift pump to create an overall fuel pressure of 21,000psi. The 94-97 7.3L Power Strokes are non-intercooled single turbocharger set up, Ford did not introduce the intercooler till 1999. These Ford Power Strokes had the option of the ZF S5-47 5-speed manual transmission or the 4-speed E4OD Automatic transmission. The factory E4OD transmission is typically weak and cannot hold much over stock horsepower and torque.