See attached pics. The dual carb setup goes pretty good. The last picture shows the dual exhaust headers by RED's.
The main construction is of wood. The spark plug depressions were made with a cutting tool I made. Spark plugs are a bolts glue upside down onto dowels. A paper sleeve is glued around the threads and a shortened nail is glued on the end of the bolt. I also used PVC, metal nuts and bolts. All the bolts(head and others were made from nuts filled in with J-B Weld and sanded down to look like a bolt).