Not satisfied with the engine noise intruding into the coach I added additional dog house insulation with mixed results. What I discovered after searching for the source using a DB meter was that most of the noise was penetrating through the firewall. Many class A firewalls are constructed of plywood with minimal insulation applied between it and the carpeting. Another source of noise was the chassis A/C return air register on the passenger side of the firewall. When open the engine noise enters the coach.
Historically, Ford V-10s have been noisier due to their higher engine revs but since introducing the 5 speed tranny noise has been reduced somewhat. I have just learned to live with the noise.
