The "internal memo" wasn't, in reality, a FoMoCo internal memo, it was a memo from the NHTSA to all US car manufacturers including Ford. As you're aware, this wasn't just studied in your law classes, it's been studied in law classes across the nation and hailed as the acme of product liability success. However, since it's been so studied, plenty of new and accurate information has come out. It seems the lawyers, news media, especially Mother Jones, etc. were lying, big shock. Regardless, the lies still created "a public relations nightmare for the ages". In a 1991 Rutgers Law Review article by Gary Schwartz, he notes that everyone's perceived ideas about the fabled "smoking gun" memo are false (the one supposedly dealing with how it was cheaper to save money on a small part and pay off later lawsuits). The actual memo did not pertain to Pintos, or even Ford products, but to American cars in general; it dealt with rollovers, not rear-end collisions; it did not contemplate the matter of tort liability at all, let alone accept it as cheaper than a design change; it assigned a value to human life because federal regulators, for whose eyes it was meant, themselves employed that concept in their deliberations; and the value it used was one that they, the regulators, had set forth in documents. I believe it was the garbage rag Mother Jones that was the source of the lie that the NHTSA memo was a FoMoCo memo. In that same article Schwartz also points out the actual deaths in Pinto fires have come in at a known 27, this number has been verified numerous times throughout the decades, not the thousand or more that the public was made to believe. Schwartz also wrote, "the Pinto's safety record appears to have been very typical of its time and class. In 10 years of production, and 20 years that followed, with over 2 million (there were actually over 3 million) Pintos produced, no more people died in fires from Pintos as died in fires from Maximas". All these facts have been verified numerous times over the years by other reputable sources.
The supposed design flaw of the Pinto was that in a heavy enough rear end accident, the front of the gas tank could come in contact with a bolt on the differential, rupturing it. It's important to note that the supposed problem was only with the sedans and hatchbacks, not the station wagons. Through testing it was found, however, that it was extremely difficult for the gas tank to come in contact with any bolts that might be able to accomplish this, unless the car was hit from behind at over 50 mph. In the autopsy for the initial accident in '78 that started this controversy, it was shown that the occupants died from the impact, not from the fire (the accident was caused by an inattentive driver in a chevy van driving onto the shoulder and hitting the parked but running Pinto from behind at over 50 mph). The biggest problem was in a hard enough rearend collision the gas tank could shift, and the filler neck could pull out of the tank causing a fuel spill. A number of our Mopars have the same potential problem with the filler neck behind the license plate. In a rearend collision the tank could shift, and the filler neck could pullout. I suppose in a hard enough rearend collision it could drive the filler neck through the bottom of the tank, of course the occupants would most likely be dead from the impact anyway, so does it really matter?