Lead additive, which one is best?

The additive jelled because the voc's were able to evaporate through the porous plastic of a milk jug. The additive was probably still perfectly good, and would have reliquified when mixed with gasoline. A simple test of this in a can would have sufficed.

The N series engines are designed to run on unleaded. They pre-date the addition of lead to gasoline. Other engines are different.

The EPA does allow a minute percentage of lead to exist in unleaded gasoline. It's 0.05 grams per gallon. At that level, all sorts of record keeping must happen, so most of the refineries don't bother with any lead, avoiding the paperwork.

Now, if Jack Podell were to be slimy, he could drag a chunk of lead through some gasoline additive (usually tolulene anyways). He could then claim that some of the lead came off, and is now in the additive. Viola! a true leaded additive (wink wink, nudge nudge). He's carefully not saying how little lead is actually there.

I don't believe the FTC has any laws or regulations governing the claim of lead in fuel additives, so he would be able to squeek by them with this bogus claim.

On the other hand, he could really be marketing a true lead additive. If so, when the EPA gets wind of it, they will prosecute the heck out of him for it. They would also prosecute the heck out of Hemmings for publishing the ads. Hemmings does have some legal liabilities for the types of ads they run.

Hemmings is not stupid. They've tangled with the EPA before, and don't want to be on the losing end of a dispute with them. So in my opinion, Hemmings allowing the ads to be published make it all the more obvious that Jack Podell is just a shyster marketing a rip off snake oil.