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Re: Taxable Horsepower

From: Bernie B.
Remote Name:
Date: October 03, 2003
Time: 16:27:27


Taxable horsepower is determined by the following formula, which was put into effect by the British Government around 1921 to raise revenue (to build and maintain roads?) according to a bit of research. Some old timers on this site might remember seeing taxable horsepower listed in the NADA used car price books, as well as elsewhere. The formula is: Bore squared (B^2) times the number of cylinders divided by 2.5 (N/2.5) -- That means an eight cylinder engine has twice the taxable horsepower of a four cylinder of the same bore. The formula ignores crankshaft stroke and total displacement. This formula would rate a 383 at more taxable horsepower than a 413! (A 383 "B not "RB," that is) It appears the expression "Speed costs money, how fast do you want to go?" has more than one meaning and has been around for quite some time. Have fun with your calculators! PS - AMA is indeed Automobile Manufacturers Association as some one pointed out, referencing the 1957 Racing Ban.


Last changed: July 19, 2018