[123pugsy]

I would weld them on.

Don't know how good that gasket is. I make all my own, never a leak or blow out. Never loose header bolts either.

Looks like I was making that same gasket at some point:

 

[69SS454]

Weld or slip fit and clamp to the pipe. Use the flange gaskets and bolts but copper gaskets will last longer. Orient a flat side on the bottom for more ground clearance.

 

[Bob Tiley]

No welding needed

 

[69SS454]

No welding needed

How do you attach your flanges to your pipes?

 

[bracketchev1221]

If you are saying the 3 bolt flange ring spins on the reducer, I have never welded the ring to the pipe. Weld the reducer to your rear exhaust and bolt the flanges together.

 

[RickSBC400]

If you are saying the 3 bolt flange ring spins on the reducer, I have never welded the ring to the pipe. Weld the reducer to your rear exhaust and bolt the flanges together.

Yes, this is what i'm saying. I was curious if there was a standard or not for this. My main sensitivity is to exhaust leaks bc the o2 sensor.