If it's not spinning the tires all the chassis work in the world isn't going to do much. I would concentrate on why it's down on power. Does it bog? 4.10 with 30" tire isn't helping. If the gear is what you have, try to borrow a shorter set of tires. What intake? What size PTC is it, 9"? 3800 flash seems pretty low with that many cubes. Where is the timing? I don't agree that 99 mph is 10.70, That's optimal. My street car runs 7.0@100 with low 1.50 60 ft. Most bracket cars I see might go 6.90 at that speed. The basic parts are all there.Right now it looks like it's making about 600HP. That combo should be good for more HP.
Doug