I think i am right on this..... and am the first to respond woo hoo...
I would say that that is wehre the mechanical fuel pump would attatch on a JDM engine with the carbs...
The blocks are mostly cast out of simalier molds..
I was doing a motor swap on a friends 96 sunbird the other day that had D.I.S and there was still a hole in the block with a plug into it that would hae been for the distributor on the older version of that block....
ciorrect me if i am wrong.... but i am guessing fuel pump...
if not that jusging on its location i would have to say its a non cutout port for vtec solenoid and pressure switch. . .
chris