Scott,
the valves are chrome plated brass.
Mike,
You can put a 3/8" T-swivel in the off-board port instead of an L-swivel and then branch to Solenoid/ orifice on the O2 side and BOV (manifold block) on the dil side.
But the block was mainly designed for our BMCLs, in that cofiguration the Solenoid/orifice and BOV are fed independently. Tryin' to keep it simple
