What kind of dyno was it? I had mine dynoed on a mustang 1000 dyno and had similar build and I made 305 hp and 416 torque on the dyno, but changed up carb and timing quite a bit and it picked up an additional 20 hp. Their is still more in it. I just have to find time to play with it more!

Here is some ideas. I use to run a 750 eddy carb, and it needed to be jetted up 2 sizes. I also found that my 440 was best after setting timing at 35 degrees at 3000 rpms.

If it was me I would call Don Gould over at FBO and discuss with him your build and see if you can get more out of it. He does a lot with mopars and could give you some clues.
He's currently building me a distributor for my set up and I think I'll get more out of it.

Mike