Took the Scamp to the track for the first time and...
I think you have a very nice combo as far as the bolt on parts. I do wonder about how efficient the converter is though? Tire diameter & rpm thru the lights may tell some information in that regard.
As you mentioned compression, it's always a possibility that you have one of the production engines with the pistons pretty deep in the hole? Add a fairly thick head gasket, and the cam duration with the .484, and it could be fairly deep in the 7's. The plus side is you can crank a ton of ign. timing into it and that will help mask that problem.
One other thing to ask is, do you know the weight in race trim with you in it? I ran the 13.5/99 numbers @ 3300lbs and came up with a round figure of 265HP. I know it sounds low by 440 standards, but actually may be a reasonable number considering the other factors.