perhaps a srt owner would be willing to provide observed speeds at 50, 60, 70 & 80 mph [in top gear].
with this data, [as well as the redline] one can extrapolate the max top end.

adding boost and pulley's do not add to the rpm/final drive ratio as it relates to speed. they merely help to get you there quicker [hopefully]

1000 hp @ 1000 rpm does not equate to 500 hp at 7000 rpm.