I found out about the 451 400 strokers back in the 1980's from Chrysler Power magazine.
Back then 440's were fairly expensive, but 400 blocks were super cheap.
The problem back then was there were not much of a good selection of stroker pistons, and no inexpensive stroker kits.
Chrysler Power was running modified stock cast pistons in one of the engines, and found that they did not have the pin boss strength for high RPM.
I got my first 451 stroker around 1991? At the time I had moved, and did not know any machine shops, so I called Chuck Senator at Muscle Motors and had them build me a 451 short block with slightly dished ROSS pistons (about 11:1 compression with the B1/BS heads), and the mild 251/251 @ 0.050", around 0.600" lift Ultradyne solid roller cam. Then I ordered up the new to the market Brodix B1/BS heads from Koffels with their stage 1 porting, 1.6:1 rocker arms, sparkplugs, and cut-to-length pushrods. Bolted those together with a Milodon low profile 7-quart oil pan, Mopar M1 intake, and 2" hooker super comp headers.
That engine made about 500 HP on the chassis dyno as it was run in the car. I think shift around 6,100 RPM? I reved the engine many times to 6,500 RPM with the stock 440 crank and rods (knowing the rods were the weak point.)
As the video points out, the stroker kits avaliable now make it an easy choice to build a stroker. I think there is actually more piston selection for the stroker combinations, than for the stock stroke 400 and 440 engines. They also don't add much to the cost of the engine build.
Also, as the video points out, the cylinder heads should be upgraded if you want high performance. I agree that rebuilding the stock iron heads is almost a waste of money if looking for performance. I disagree with the video on the cost of Mopar heads being less expensive? Sure the stock replacement type Edelbrock E-Street heads, RPM heads, and 440 Source Stealth heads are fairly inexpensive, but when you start talking high performance heads like INDY, Edelbrock Victor, Mopar Stage VI, Trick Flow, and Brodix then the cost of the heads and rocker arms is likely more expensive.
I never seen the Speed Master or Promaxx heads, but I think they are a knock-off of the Edelbrock heads?
There are also some lesser know heads like BullDog, the Stage V hemi conversion heads, and modified heads from other shops (Marsh, Toth, Porter...)
Not sure if the SideWinder head is a different casting than the other Edelbrock type knock-off heads or not?
Most of the stock replacement heads use the stock intake port opening and 2.14"/1,81" valves, Where most of the High Performance use the larger Max Wedge intake port opening and usually a larger intake valve around 2.20+"
Many of the stock port opening heads can make over 600 HP. On a 500+" stroker, I believe the larger Max wedge port heads would be a better choice in a high performance application > 600 HP.