Ford Challenger 260 V-8 Torque and HP Curves

[ew1usnr]

I could not locate a horsepower and torque curve for a Ford 260. I took what information I could find, extended it using the equation HP = (Torque*RPM)/5252, rearranged as Torque = (HP*5252)/RPM, and extrapolated what was missing to create one.

The result is probably pretty close to being correct. It clearly indicates that the 260 was designed to deliver low end torque (red line) rather than high end horsepower (blue line). The engine red lines at 5000 rpm.

Challenger torque curve.jpg

Notes:
The equations equation HP = (Torque*RPM)/5252, rearranged as Torque = (HP*5252)/RPM are referenced here: http://www.epi-eng.com/piston_engine...and_torque.htm
I knew three data points, 0 rpm = 0 hp, max rated hp is 164 hp at 4400 rpm, and max torque is 258 lb-ft at 2200 rpm. I also used the following info from Carroll Shelby who dyno-tested a stock 260 engine and reported the results in Hot Rod Magazine, October 1963. Shelby reported the actual peak horsepower was 86% of the Ford-rated 164 hp. I converted Shelby's figures back to the rated figures by multiplying his figures by 1/0.89 so as to display the plotted curve in the Ford- rated values.

Shelby dyno-test.jpg