i bought a blueprint engine in 2011 with 238/238 @50 thou cam , air gap, dyno'ed with 750 edelbrock and dyno sheet said 415 horsepower ,486 torque with stock magnum heads. i think intake manifold is the bottleneck
In my mopar dyno experience I have found a few trends that support one of our communities engine builders claims.
1. Mopar engine do not like restriction above the heads because the heads are the restriction.
2. They like bigger plenums and bigger carbs. EVERY time I have had a a mopar engine on the dyno, it liked a bigger plenum and a bigger carb.
I would almost guarantee that your engine would make more HP with an HVH siper sucker on that RPM intake. It would most likely respond well to a Victor intake. It would most likely respond well to more CFM or true CFM.