You should check your timing with a piston stop as well as your carb opening fully. With what you have at that weight you should be going at least 106 MPH, are you running at a track much higher than sea level.
This.
Something is amiss here, as that car should be running better than what you're posting as is. Would be very curious to know what the air conditions were that day as well. I'd spend a good weekend going over the car, and fine tuning what you have, before I started throwing money at it.
