Daze and Digz - I found a chassis fabricator (modifieds) who thinks the cast steel units can be shortened with preheating and stress relieving.  He's going to weld the 3" (removed) pieces together and do some destructive testing to check for strength.  If there's any doubt at that point we'll fabricate something from scratch.  These control arms have a fairly complex geometry - the hub and diff pins are not parallel, plus they are in different planes (the diff end angles up from rear to front while the hub is level).  The plan is also to add an internal vertical gusset down the center by drilling and spot welding.  The thought here is that should the welded joint ever fail there would be some structure to keep things together (more or less).  My thought was to plate over the joint to reinforce things but the fabricator thought this would induce stresses and increase the chance of cracking - I guess the idea is for these things to flex torsionally.  I'll post a picture when I get them back.  Unfortunately it will be a couple of years before I get the beast on the road to know if this works.  Thanks again for your help.  

Here's what the lower control arm looks like.  I'm not certain if it's cast steel or cast iron.  Thanks.

I'm installing a 2001 Jag XJR drivetrain (engine, trans and read end) into a '65 Jag Mark 2.  I need to narrow the rear approx. 6" overall, and I notice a lot of you are doing this on the older units with tubular lower control arms by cutting and sleeving.  The later units have steel or iron castings with a flattened oval cross section.  I tried to attach a pic but can't do on my first post.  Does anyone know if these can be shortened or if the older style lower control arms are compatible with the later diff and hub carrier?  Finally, can a good machine shop fabricate something from scratch, and if so any recommendations in New England?  I'll appreciate any and all advice.