Water Pump Gear Removal

If anyone can help me with this it would be greatly appreciated. I am currently installing a heavy duty timing chain set on my 95 camaro Z28 Lt1 Gen II. i have removed the cam sprox and the crank sprox but i cannot get the sprocket off the water pump drive gear/shaft i cant even get it to move, it looks like it might come out from the back or be tapped out from the back (inside of intake manifold) thx guys