Unblocking EGR Passage, How Far Does This Passage Go Into The Manifold

Hey Guys
I’m stumped, this past weekend I cleaned my egr ports (6 of them on top) along with the passage (rectangular hole) that leads to the ports. The 6 ports are flowing air perfectly but the egr passage isn’t. Prior to cleaning and after I was finished, when I applied vacuum to the valve, the car didn’t stall. Valve is clean and working properly.

My question is:
How far does the egr passage (rectangular hole) go into the manifold, I was able to get in there with a wire a good 5 inches, filled the hole with throttle body cleaner, etc. but I still can’t get any flow to the ports.

Car is a 2000 Prelude, all stock, H22A4.

TIA

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