LaPlante LPSS-7538 Air Compressor Pump. 2 Cylinder, I Configuration. 12 Flywheel Flywheel INLCUDED with package! 5.87 from the left mounting holes to the right mounting holes. 5.81 from the front mounting holes to the back mounting holes. Difference between the 7550 and the 7538 pump. The 7550: 75mm bore and a 50mm stroke. The 7538: 75 mm bore and a 38 mm stroke. The 7550 goes further up and down with each rotation, giving you better performance at the same RPM. The 7550 has both holes threaded with one 1/2″ female port, and the second 1/4″ port coming with a bolt. The 7538 is different in that it has only one 1/2 female port. The item “4.5 HP Air Compressor Pump 155 PSI Cast Iron Replacement Pump LPSS7538 Sale” is in sale since Monday, June 10, 2019. This item is in the category “Home & Garden\Tools & Workshop Equipment\Air Tools\Air Compressors”. The seller is “aircompressorsandparts” and is located in Amarillo, Texas. This item can be shipped to United States.