Clois,
I'm using the Tony B. cast aluminum COBRA T-pan and the Melling pump as well. It's been several years since I built my engine, but if memory serves me correctly, this setup uses the stock pickup tube.
I later bought a Canton pan that
did require a special pickup, but have never installed it.
The pickup tube just presses into the pump, maybe you just need to rotate it a couple of degrees. Whatever you do, tack weld the tube to the pump housing before the final installation of the pan. If the pickup comes out it could cost you the engine. Also, make sure you have an acceptable amount of clearance from the pickup screen and the bottom of the pan, you don't want to restrict the pickup.
I'm also using a windage tray that sandwiches between the
oil pan and the block (with an additional gasket)and this assembly spaces the
oil pan down an additional 1/8 inch.
Hope this helps,
Steve