Once I get the first piece perfectly drilled I then match drilled the second piece by using the first one as a template. Once this is laid out I can tap the vent holes to accept the fittings for the hoses. On final assembly this needs to be sealed with a gasket or sealant or both around the vent holes. If a gasket is used it needs to be uniform around all the bolts to prevent distortion of the end plates.

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