entirely possible if engine was replaced with a partial engine over the years it is not in the factory Merc location.
If you look at the photos of the rear of the engine in this partial engine package there is a bracket between distributor and carb where they are located in a lot of non OEM replacement engine packages. May be there and hidden ?
This BRAND NEW 5.7L Vortec GOLD package is great for those that need a little more than just a base engine or long block, but still don't quite need a complete engine package. This 5.7L GOLD package is rated at 315 hp @ 5000 RPM at the crank and will fit,