There was a book out in the late 70s about how chrysler did there engine dyno program.If I remember right chrysler was doing rear wheel horsepower and saying it was crankshaft horsepower.The 340 was really over 300hp amd the hemi was over 500hp.The 440-6 was close hehind the hemi. insurance reasons was a factor for low Hp. remember these cars was ment to be driven by are grandmoms. Mark