In order to get a nice tight plenum to cowl fit, I decided to build up the joining areas with micro. The micro was laid over the taped off area of the cowling and then pressed up onto the plenum and left to cure. After cure, I sanded the the transition to a perfect flush mating joint and then removed the cowling. I then brought the plenum home, sanded it down and sprayed filler primer over the entire plenum as another guide coat. After a couple more rounds of filler, she will be ready for final primer and paint, but not until I see this idea improve the oil temp issues.
