But when you make the tophat you can make whatever lead in you want on it, any lead in on the bearing itself will have no effect at all. I'm well aware of what the problems are with the standard sleeved bearing because I've been there, the only difference was I realised it wasn't going to work before I even fitted it.
We have a 3500s suffix b gearbox that has been re-built and fully torqued up but not yet installed in car or run. It turns out the bearing 576208 we installed is actually a modern 'standard' one with a plain sleeve pressed into the inner bearing race to reduce the inner diameter down to the same as the bespoke 576208. The sleeve is a press-fit into the bearing and is the same width as the bearing and is not the "top hat" design as discussed in the old thread linked above.
As I say, the output flange is fitted and the rear output flange nut fully torqued up. The gearbox rotates freely in all gears but obviously hasn't been run or taken any load.
But old fears come back to haunt, and as the time to install the gearbox approaches our concern is that by using the bearing sleeve it will only cause issues in the future, and whether we should bite the bullet, part-dismantle the gearbox and replace the sleeved bearing with with the correct 576208 part. If we absolutely have to, we'd rather fix it now if the sleeve definitely will cause problems in the future. Wadhams have still 576208 available for £174 (!) and we have heard that another popular P6 supplier may soon be doing a short re-manufacturing run of 576208 bearings too.
a) not worry - if the mainshaft is turning freely now then there won't be a problem in the future even after the engine run and car driven in anger.
b) re-dismantle the gearbox now to replace the bearing now, as the sleeve will cause the gearbox to fail in the future?
Any advice now gratefully received, especially from those that have been through this issue and successfully / unsuccessfully used a sleeved bearing!