Drive side main bearing

[KeithJ]

Timely topic and very interesting as just rebuilding my A10SR engine.

The idea of using a bearing with the rollers in the outer sounds like an excellent option which I plan to use. 

I have been offered an NSK NUP206E C3 30X62X16 for £24 inc VAT which appears be very reasonable price which made me wonder if the NSK brand a "Quality brand”? 

The NUP 206E, not sure what the E denotes, has 13 rollers.  Presumably the same bearing can have different numbers of rollers, if so is 13 the “right” number?  Is it the more the better?

Would using the NJ be simpler as I can’t see any particular advantage for using the NUP with the extra part?

Thanks to all the folks who have posted on this.

[Servodyne]

I've been running with a NJ 206E M C3 in mine for a good while now. I'm not sure what the loose ring on the NUP is supposed to do so I opted for the NJ and if you go for the M version it comes with a brass cage as well which gives a quality feel about it. When I compared these bearings with the offerings from some of the well known BSA A10 suppliers they look much more heavy duty with the much wider rollers.