One thing you need to remember is what happened back when those 60's motor mounts were failing in the early 70's.The early cars with a mechanical linkage from the gas pedal to the carb would go to full throttle when the early engines would torque up after drivers side motor mount failed.That caused many accidents and unintended acceleration.
Then the recalls started but did they replace the motor mounts ???
Later Chevy's made after 1968 had a motor mount with a safety interlocking piece or latch that only allowed a small amount of movement after the MM rubber would fail and then separate allowing the engine to rise up about only an 1/2 inch or so. Plus those newer Chevy's (and B-O-P's too) had throttle cables
not steel linkages,more safety from the factory.
So what to do about all those millions
of Chevy's V8's already produced and sold with the defective MM's.Just replace the mounts with the later safety strap motor mounts ? No way that would cost way too much.No, they came out with a cable and bracket piece that would catch
the engine when the motor mount failed and not allow the engine to torque over and jump up when the MM failed.
The cable didn't actually hold the engine (not unless the MM rubber had ripped apart) it was just looped around the heaviest part of the frame near the motor mount to catch the engine should the MM fail in the future.Remember Chevrolet sold a million cars in just the full size Chevy B-body line alone
Replacing ALL the motor mounts in the Chevy's built between 1958 (IIRC)and 1968 would have cost a fortune.No,the cable and brackets was the quick fix and it worked.And more than likely the hot rodders and drag racers with their chain limiters gave the engineers that idea.
Somewhere in my box of leftover parts I still have a set of the recall bracket and cables,I found them in the trunk of my 1965 Impala 283.
Bottom line,the recall cable's didn't actually hold the engine and the hot rodders chain doesn't hold the engine either, they just limit the engine's movement.