As a mechanical engineer, I fail to understand that point. The best you can do is apply the brakes to just before the tires skid (then coeff of friction goes down), and drum brakes can easily skid the tires.
The stock drum brakes will in no way, shape or form lock up the 275/40/17's I have on 17x9" rims all the way around on my Challenger. Not only can they not deal with that amount of traction, they can't deal with the added rotating mass.
The stock drums were ok for the stock tires, which were bias ply's. They're less ok for stock sized radials. But if you're going to run 14x5.5" rims and hockey puck hard BFG T/A's, they'll still do the job when adjusted properly, dry, and not overheated (notice the number of conditions there).
If you're upgrading to modern rubber though, you need to upgrade the brakes right along with it.
@plumkrazee70-
A '70 340 car should have had 10" drums from the factory, which is a good thing. Properly adjusted they'll do ok stopping a relatively stock sized tire/rim. I'd still plan on an upgrade, and I run 11 3/4" disks and 11" rear drums on everything I put on the street.
If you don't have a service manual, go here. No '70, but '71 was the same for brakes...
