Straight 6 Engine Identification

[63C20stake]

I know this topic has a lot of coverage on this Forum and various others. However my particular 6 does not fall strictly into one set of specifications. Do i have a Frankenstein? Okay so I have a 63' C20 with a stake-side bed, the original owner told me when i bought it that it had a 292. However as I am replacing the clutch, and reading the manual my conflict begins. The Clutch currently in it is a 10" Diaphragm with the 168 tooth flywheel. My manual says a 10" Diaphragm did not come with a 292 but with a 230. It says the 292 only cane with a 12"coil. Next my gallery covers have a height of 4" signifying the smaller engine. My fuel pump is centered on the block, not offset forward. The motor Mounts are staggered with the passenger side forward (292). Finally the number on the block 3789404, comes up as a 292. What is going?