arwally, i have sent you a PM.

thanks everyone. Think I'll opt for later pair.

I personally have had one of those arms come apart at the welded seam under competition , I would advise you to change to the later cast steel ones. BOBB

I too have heard of the welded arms coming apart at the seams, but Graham at Heritage tells me he has never seen one do that, even under racing conditions.

Not sure why the change but be sure to magnaflux the arms for cracks as they are welded and can fatigue over time. Also the two holes must be line bored to size.

Life is like installing windscreens, it takes a lot of elbow grease and some personal lubricant. 

I'm redoing a very early Mini that has the welded steel fabricated rear radius arms. These use the two bronze bushes instead of one bush/one bearing. Are there any inherent problems or wear on these early ones, ie why the bearing change? (plan on some track days and occasional autox) Also on earlier threads mention that align boring/reaming of the later ones uses the needle bearing as a basis for alignment, what about align reaming of the two bushes? The shaft looks fine and seems to have been well lubricated over it's life. Thanks arwally