[Ron61]

Doug,

Here is what my Ford Performance book says about the 289 HiPo. "The 289 HiPo was not just a dual exhaust/cam/four barrel advertising ploy. It consisted of a stouter block, a high RPM balanced nodular iron crankshaft, forged steel rods with 3/8" bolts, a solid cam with a healthy profile, and screw in rocker studs in the heads. It also had streamllined exhaust manifolds and a dual point distributor." It also says that only 17,000 were produced, but mainly the biggest difference is in the stouter block.
Hope this helps.

Ron