On my late-model HG with the IXB3 engine, the intake/exhaust manifold sits so low that the carburetor will not fit with the magneto installed. So, mine has a little offset adapter that puts the carb. out of the way. Looks pretty weird. I had thought that perhaps the adapter was homemade. But, recently, at my favorite tractor junkyard where over a dozen HGs and OC3s sit, I saw several more like mine. I notice that the low manifolds have HERCULES on them whereas the correct manifolds have OLIVER on them, or are blank. Were the low manifolds a replacement parts kit that came with the necessary oddball adapter? I can't figure what they would work on without the adapter since any engine needs spark. On my engine, I tried installing a Wico distributor that is more shallow than a mag. but it still would not fit with the carburetor installed.
That manifold was used on hercules engines that were sold for power units, such as welders and etc, they were sold through hercules.<p> The hg never came from the factory that way.
I have seen the offset adapter on the IXB-5 engines. Those had a different style drive for the mag, and the carb had to be moved for clearance. That engine was used in welders, pumps, generators and as power units.
You'll find the IXB-5 engine in Leader tractors too. They were made right in Auburn Township, just east of Cleveland.
Blake