Custom duals to y pipe

If I blocked it either way it would be open not shut, if it's stuck shut it won't breathe

Incorrect welding the heat riser in the closed position well not cause it not to breathe, it actually directs the heat towards the exit outlet. Depending on your build if you want a heat riser or not, for me welding the heat riser in the closed position helps me in two ways, one I don’t need that gasket the goes in between the intake and the heat riser, two my intake still gets warmed from the heat but not crazy hot causing heat soak and hard starts, with a turn of a bolt I can have the heat riser touching the intake or just underneath it with a gap for that hot summer days. You can see in this photo the heat riser is welded shut on the closed position forcing the hot exhaust air out the manifold.

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