Derek, I posted this photo of a complete Dana 30 with a limited-slip diff that was used in a (US) SCCA regional championship winning 1967 1800s from '67 on to show you the effort that has been put into keeping axles from breaking here in the US. It has hubs that have been lengthened inward (the shiney area) to add support the axle all the way up to the bearing to prevent them from breaking in that spot. It uses standard Volvo hubs and has heavy-duty Ford taxicab brake drums.
I am considering selling this historic axle as a package probably next year if anyone in the US might be interested, it is located in Vermont.
Today racers and hi-performance enthusiasts use 1800E/ES axles that are the same width as the Amazon and P1800/1800s. Others use 140 series and 240 axles but both are wider.
I run the HVRRS - Historic Volvo Racing & Rally Society on Facebook @
www.facebook.com/groups/232999844689051/ A member started a post on broken Dana 27 axles recently and other members have responded. I've copy and pasted the question and replies below.
Loris Mariotto - Hi all. Where is the weak point on a spicer 27 diff for motorsport applications (circuit)? Is it the taper where the drum fits? Thanks.
Carl Helmetag - You’ll find out pretty quickly if you don’t keep the axle nuts tight.
(122S) Mike Wynosky - Yes I had one snap off in a race and watched the wheel pass me on the track
(544) Richard Reynolds - I almost rolled it when my wheel passed me on the track, mine broke a the key way, tryed custom made Ford axles, they also broke. Now have a 30 axle, the donor was 240, no problems with that combo.