Is there a possibility that the crank in the 360 is drilled for a standard transmission as was your original 318? When you ordered the engine, was the transmission type being used mentioned? I only bring this up because at one time I worked in the parts dept for a brand X dealership. The cranks for a standard transmission were different than the cranks for an automatic transmission. Standard cranks of course take a bushing or bearing to support the transmission input shaft, automatics drilled to take the converter pilot, no bushing or bearing required.
In the converter catalog I have in front of me, all 727 converter pilots show 1.810". 904's also have the 1.810" pilot except for the early ones at 1.550". There are some odd ball import and Jeep converters that have other sized pilots, but none that measure 1.797" You might want to check with the engine supplier and find out what they supplied you. It was mentioned that you might get the converter builder to machine the pilot down, and a factory pilot is not a solid piece, but is hollow. I'd also as suggested, check with the converter supplier and see what they say.
It's an engine issue, not a converter supplier issue you've got in my opinion.
I hope you can get the problem solved.
