It was necessary to modify the right intake plenum as it did not have adequate cleaqrance between the plenum and the #1 exhaust pipe. As per Bryan at showplanes, I removed the section of the plenum that was causing the fit issues. After several iterations, I was able to fit the plenum with a nominal 3/4" clearance on the exhaust pipe.
I bolted the exhaust in place for positioning. Next, I wrapped the pipe wit two layers of pipe insulation which provided the 3/4" spacing. The insulation was wrapped with packing tape to prevent the eoxy from bonding to it.
Cleco right plenum to center plenum.
The next step was to be able to form the f/g layup to the pipe insulation. This was accomplished by inflating a balloon inside the plenum.
Mix epoxy and wet out three layers of 9 oz f/g cloth.
Apply the f/g cloth to the plenum, over the balloon.
Install the plenum assembly on the engine, cleco the plenum bracket to the baffle mount.
Carefully make sure that the f/g was laying flat on plenum, remove air bubbles.