This is a response to a question about steering I posed on the MG mailing list. I need to thank Jim Stuart for allowing me to quote the material he wrote, which is found below. Out of all the answers I received, this by far seemed to be the easiest and least complicated method. My personal experiences are at the bottom.
"As in all such things, there are many ways to accomplish a given end, whatever works for you is "right", but swapping in a rubber bumper crossmember creates at least as many problems as it solves, the major one being ride height. To correct this, short springs are usually used, changing the "Ackerman" angle, creating bump steer. You also do not need the RB Xmember to provide engine clearance for either the Buick or Rover engine.
Remember, the book was written for British consumption, right hand drive, but plenty of Brits & Aussies have done the conversion with the early xmember.
I use the rubber bumper rack, use a sander or sawsall to change the angle of the rack mounting pads, lower the steering column where it passes through the firewall, & shorten the steering shaft, about 2 hours work, no welding, just some slotting of holes, a little cutting, & time spent shimming the steering rack.
You need a subscription to the V8 Newsletter, it will provide plenty of "how it was done" info. There is a link on my web page."
Below is a request for clarification that I made to Jim, I was still a little confused about where to remove material.
"The sanding/cutting is on the pads on the steering rack, not the mounts on the X-member. The mounts on the X-member are not changed in any way. Sit the rack on the X-member, run a couple of long 1/4" bolts through the holes closest to the windshield, & wobble the rack around a bit. This will show you what needs to be done better than I can describe it.
You should be using the smaller late model U-joint at the end of your steering shaft at the end of the column. The smaller joint will give you more clearance for your headers.
Once you have roughly oriented the steering rack, you will see which way the pads on the underside will need to be cut. There is not enough materiel to cut away to make a perfect match. Get as close as possible with a belt sander, hack saw, or other tool of your choice, just DO NOT USE A GRINDING WHEEL- of any kind. The rack is aluminum, & aluminum will load up a wheel, & may cause it to explode, since the aluminum will actually melt into the wheel. Forgive me if you are already aware of this, but I don't want anyone hurt because I didn't speak up when I should have.
Once you have the bottom of the rack modified, It's time to work on the top. You may notice by this point that the mounting bolts do not meet the captive nuts on the X-member at the proper angle to allow them to thread into the nuts. At this point, fire up the drill. I believe the original hole in the rack is 5/16", please verify this. Assuming it is 5/16", use a bit this size run all the way through the rack, then lean on the drill to enlongate the hole. Do this away from the X-member so there is no chance of damaging the captive nuts. Bolt the rack up loosely to be sure it will allow the shaft to meet the U-joint. When everything looks OK, mark & cut the shaft. The amount removed will be about 1-1/2". This will vary from car to car.
Since the cut end is not splined, it will be necessary to open up the end of the U-joint quite a bit to allow it to slide over the shaft. The way I do it is to remove the U-joint from the car & use a large cold chisel as a wedge & hammer it into the existing split. When the joint is opened up enough to fit over the shaft, reinstall the joint & rack. Now is the time to add washers &/or shims of thinner metal to secure the rack. Get close, you don't have to be perfect yet. When things look good, mark the shaft where the fixing bolt in the U-joint will go, & take the rack back out. Don't be tempted to drill through the bolt hole in the U-joint to make a groove in the shaft, as the shaft is much harder than the U-joint, & the U-joint will be the casualty. Best to use a small rat tailed file or a thin grinding wheel. Do not groove around the shaft as was originally done. You want only enough of a groove to allow the bolt to pass through. This minimum cutting is what will keep the shaft from slipping when the steering wheel is turned. Use a grade 8 bolt & nut to fasten the U-joint to the shaft & tighten up tight as hell.
Now is the time for final shimming of the rack. Trial & error here, the thing is done when the steering wheel takes a minimum of effort to turn. At this point, the tie rod ends should be connected so that you are actually moving the tires, even though the car is still in the air.
Two alternates to some of the above include having the cut end of the shaft splined ( I could not find a machine shop to do it) or cut the shaft between the rack & the motor mount, shorten & re-weld using a steel pipe as a reinforcing sleeve. I had this done on my first car, but it was a lot of trouble as I had to have someone else do the welding. I have done the described method on three cars not with no problems in 45,000 miles.
As always, steering is your life & the lives of others. If you are not comfortable modifying your steering, have a pro do it, or find another alternative. I assume no responsibility for your actions in this matter."
As I just completed this modification last night, let me add some personal experiences and tid bits. The amount of trouble greatly increases if you do not use the "AC" mounts. Utilizing the Non-AC mounts, I found that I had to remove a lot of material from the steering rack mounting pads to gain clearance for the oil pan. It is obvious when you do this, that moving the engine 1.5" back would eliminate most, if not all, of the interference problem. My car is a 77 body and steering rack with a '73 crossmember. I took approximately 3/8" off the rear pad and then took 3/16 off the entire width of the pad. I feared taking any more, as I didn't want to accidentally break through into the actual rack itself. The procedure went well using a hacksaw and a file. The aluminum rack files pretty easily. During installation (with engine in final location), I found a problem. I still had not lowered the rack enough to clear the oil pan. So I "massaged" the very front of the oil pan, just a little bit to gain some extra clearance. I don't believe this will hurt anything, but please do this at your own risk and only if absolutely necessary. I probably dressed back the very bottom of the front about 1/4" inch.
The second obstacle, was installing the U Joint on the input shaft of the rack. Take as much time as necessary to spread the U Joint out to fit over the cut off shaft. It is very very difficult to install on the rack when it is in place. It too me some time crunched in the drivers footwell with a hammer and punch to drive the thing on. I don't think I had the Joint opened up enough. But opening it up wasn't exactly an easy task either, I spent more time trying to remove screwdrivers, etc. that I got stuck in the joint. You'll know what I mean when you attempt this.
It looks like header clearance will be good although I don't have the headers yet installed. I can see that if you were using the AC mounts, the rear / bottom header bolt would be very close to the U Joint. This might pose a problem which I didn't have to deal with.