Mercruiser 7.4L Engine Overhaul

This was an interesting build. Customer brought us an engine out of a 1997 27' Sea Ray with a Bravo outdrive. The donor engine was a 7.4L Magnum engine out of a V-Drive inboard application. Upon disassembly it was discovered that an L29 7.4L reman long block that was swaped in. Those were originally 310HP. The 7.4 Magnum was 385HP. The donor engine had burnt valves and after a discussion with the owner we proceeded with overhauling this engine and most likely getting custom tuning done on the MEFI 3 Delphi ECM. The custom tuning was done by obd2allinone.com. This was a hybrid situation since the cylinder heads, cam, and compression are different from an L29.