SRT Exhaust manifold down pipes??

What are you guys doing for cat free manifold down pipes? I was looking through the Walker catalog and could not find big enough 2 bolt flanges. I saw some online but unsure if they would work and did not come with the pipe.
What are you guys using? Is there a part number for easy access or are you just having a muffler shop make them? I just need the flange and about a foot of pipe for now to weld an O2 bung into and test fire the motor. The manifolds I have are 3" pipes.
This is the manifolds I am using:
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