Does this engine have a mechanicle fuel pump? If so and the oil smells like gas the diaphram in the pump may have ripped and could be dumping fuel right into the crankcase. This happened to my 355 and I couldn't figure it out, my engine started making alot of noise and was blowing oil out of the breathers. The reason was that the gas was breaking/diluting my oil. I got a new pump, flushed out the oiling system with some 15w 40 and an oil pump primer, then I put some fresh Mobil 1 in it with a new filter and never had that problem again.
If your engine feels like it has less power it may be because the lack of fuel pressure due to the ripped diaphram. A quick way to check if you don't just want to change it to be safe is to look for a small hole drilled into the pump housing and if it is weaping gas then the diaphram is torn.