First time down the track

Interested. What mph do you believe it should run?

450 at that weight it should easily run 112-114. Spinning tires usually doesnt kill MPH as much as they do ET.
My little brother has a 71 Dart street car. Bone stock 70 340 in it with mild aftermarket cam, headers, intake, 750. Has 4.10 gear and 3000 ish convertor its been 12.90 at right at 104 to give you a comparable MPH.
Your off at least 10 mph somewhere. Thats a ton