@Big_John is highly accurate in his assessments.
In doing any brake job, the normal procedure is to have perfectly smooth and flat surfaces for the frictions to rub against. "No pull, no brake pedal pulsations", BUT if there were no brake pulsations to start with and the surfaces were not gouged/grooved, then no real reason to cut the drums, from my experiences. It might take a little bit longer for the shoes to get "mated"/worn-in on those surfaces, but when that's done, then there can be marginally MORE actual braking surface for the frictions to work with. But every mechanic/DIY-er wants things to be "the best" as soon as the job is completed. NO problem with that, except that "the best" only happens after the frictions have gotten hot a few times from use, i.e., "break-in". Take ANY fresh brake job out and nail the brakes to test them under emergency situations and in many cases, they will NOT stop straight, nor will they ever stop straight consistently after that, by observation. IF the friction surface on the drums or discs is NOT to OEM cut/ smoothness specs, then things can get worse, too, by observation. End result, in some cases, all of these "make it the best" activities can actually make things worse. These things used to be known years ago, to advise the customer to use "easy stops" for the first several stops, which can be done, but NOT to go out and do any emergency situation stops for a while, unless condititions dictate such.
ONE thing about new drums is that they might well need to be "cut", depending upon how the box they were in was stored on the shelf. If stored vertically, they'll probably have a bit of an oval shape to them. If stored horizontally, most probably they will be round. The vertical storage can result in brake pedal pulsations, too, so best to put some miles on them before they are machined round. Not unlike how a seasoned engine block is better to machine than a new/"green" engine block.
Now, there is a procedure to "break-in"/"wear-in" new brake shoes and pads. Something like 10 easy stops from 45mph, followed by a complete cool-down before 10 moderate stops from 60mph, followed by a complete cool-down. This heats the friction material to "cook-out" any gasses in the "green"/new friction materials. Should the drum/disc contact surfaces be too rough and do not have the "non-directional polish" on them, the rougher surface will cause the frictions to heat and fade much quicker, by observation. So, NO panic stops until all of these things are completed, for best results and long-lasting braking performance, from my own experiences.
Disc brakes do have better fade resistance than drum brakes by design. But a drum brake system with quality frictions can be a better-stopping system than a disc brake system with poor-quality frictions, even in the fade resistance criteria. But with federal standards and such, this can be less of a concern than it was in the middle 1960s, by observation.
Sorry for the length. Many thoughts and experiences,
CBODY67
