Looks like that block could use a good cleaning. I don't know about an ITR oil pump, but I'm running a Toda Hi-Flow pump and it works great with the extra req'd for vtec and the piston oilers.

As for your main seal issue; I'm assuming your crank is scored pretty bad? You can shim behind the seal a little when you replace it, and this will make it run in a slightly different spot on the crank.