Hello all. As my user name might imply, I am in the process of having my 04 STi short blocked. From what I have read, the casting number for the latest block was the 703. I have my car at a dealer here in Richmond and they are completing the short block and turbo replacement for me.

I know the Subaru part number for the short block is: 10103AC030

I was assuming the casting would be a 703 but my technician tells me it is a 705. Unfortunately, the tech could not tell me if the crank was black indicating a nitride crank.

Can anyone tell me specifically what the difference is between my original 04 block and the new short block with a 705 casting number?

Just wondering if the new block will be a down or up-grade.

Any information would be appreciated!