My Dads cousin bought a new 1969 Swinger 340, 4-speed, & 3:91 Sure Grip. He ran it in the pure stock class at Lions Drag Strip. He said it ran a best of 13.80! At an est. 3300 LBS. this comes to an est. rear wheel horsepower of 249, with a flywheel reading at 300 horsepower. I think an NHRA rates these at 315 horsepower.
