Here's what I have learned about Superblends.
1. Superblend is a marketing term Norton came up with when they went to the (e) designation bearing to solve main bearing failures that occured with the Combat engine. Bearing manufacturers don't know the term
2. The barrel shaped roller idea is a bit of an urban myth.
3. The E designation stands for extreme service. These bearings are rated for a higher shock load than the same size bearing without the E designation.
4. The bearing change at Norton did seem to solve the problem of mainbearing failure. They also made other changes at the same time, ( stronger cases, stronger crank, bigger engine, lower compression) so it's hard to know what exactly happened there.
I was able to get e spec bearings in the 30x72 mm size, not sure if they are available in standard Vincent size.
From reading about Picador testing, the crank issues were with mainshaft failure, big end failure and flywheels coming loose, walking out of alignment.
The problems were solved with the Picador crank which used special mainbearings that had standard OD but ID enlarged to 1 1/8" for the oversized Picador crank mainshafts. It also had a non serviceable crankpin that had a full press fit, no nuts used. The pin also went all the way through the flywheels at full diameter, it wasn't shouldered down.
This gave a much greater connection area, maybe three or four times as much as the standard crankpin to flywheel connection.
It was also at a higher interfence fit than the motorcycle engine version.
Those were referred to as a five ton fit ( hydraulic press reading) while the Picador crankpin to flywheel was at ten tons or more.
This setup was tested to 115 HP on a Supercharged engine and survived.
It also survived a continuous 65 bhp for 12 hrs as needed for the Picador engine.
Standard cranks came apart in as little as 15- 20 minutes at 48 bhp as produced by the Shadow engines ( not 55 as advertised in Brochures!)
Jim Comstock plotted the shape of a new "Superblend" roller bearing and found it to be the same as any standard roller bearing.
He had to destroy a new bearing to make the video. Kind of a waste but he wanted to know if there really was this shape difference as is so widely believed.