weight/mph on ET/MPH From Horsepower Calculators is FWHP, been using it for 35+yrs, when I was racing and still do today for friends cars and its as accurate today as it was for my cars then if you use it correctly, and yes it works on motors that I know have been dyno'd here according to track known weight/mph under good conditions. I never weighed my car so yes its an educated guess knowing my weight and curb weights which vary, could've been 3550 I suspect so could be a few more hp and the reverse of that if less.