68 Dart first time out
461 hp at 3400 should run in the 117-119 range with an ET down in the 11.30 range
My guess, the converter isn't near what it could be. Probably a big slip ratio in it being an 11" unit. Get a good converter and I bet it picks up .3 and 3-5 mph alone.
The carb is holding it back as well. Did they dyno it with that carb? It could use every bit of a 950hp.
Porting would pick it up for sure. There's some hp getting them opened up.