Many folks want to know what is good practice and insight into rebuilding their MGB engine.  They also are looking for the best performance possible once it is completed. The PDF file you will find at this site, http://www.sterlingbritishmotoringsociety.org/files/mgbtunings.PDF , is the result of Steve S. of Virginia's long hard work to provide an excellent guide and discussion of the various methods, procedures, and options available to any MGB engine rebuilder. Altho many folks may not want to go as far as he has, it is worth the reading to better understand why some procedures and choices are better or worse than others.  We all do what we can, but there is no reason not to look at the big picture when contemplating an undertaking like an engine rebuild. You might as well get the most bang for your buck, and Steve's advice and keen insight is well worth consideration.

Getting rotary shaft seals to seal properly has several aspects that are not always understood fully.  The RL Hudson Company, a seal maker has an excellent site set up to give you the full low down on what will make your rotary seal replacements trouble and leak free for the longest possible time. It is one of the best instructional sites on the internet.

http://www.rlhudson.com/publications/pub_shaftseals.html

When beginning a tuning program, one of the factors that sometimes leaves folks guessing just what they should do, is the choice of main metering needles used in SU carbs.  For those of you who want a bit more scientific approach to making this choice than "cut-and-try" or sanding your needles or some of the other methods your may have heard about, there is a small program which you can download for free (or you can pay for it and get full functionality) is one called WinSU.exe.  You can download this this useful program at this site http://www.winsu.co.uk/

Short of adding this program to your perhaps already loaded computer, you can also go to this site, http://www.mintylamb.co.uk/suneedle/
This site will give you the opportunity to simply compare the profiles of all available SU metering needles.  You first select your jet size, 0.090", and then pick up to 5 different needles whose profiles will be shown to you graphically together on one screen where you can make your direct comparisons.  Pretty easy, and much more informative about the relative relationships of differing profiles to visually oriented folks than a simple listing of needle station size numbers.  In short, you can simply see when one profile veers off wildly or mildly from one of the standard factory chosen needle profiles very easily.

Other, useful programs, such as the original DOS based Haystack (as in finding a needle in a haystack) and several other SU related links can found at Paul Tegler's excellent site, http://www.teglerizer.com/sucarbs/index.html  All of this same info. I have been using and recommending for years, so I know it will make you smile and it will increase your genuine understanding of these often misunderstood carbs. SUs are not hard to master, and the folks who have created the sites Paul has compiled (some of the same I've posted here) have taken the time to become experts about how they work and how to work on them, and that will give YOU the maximum satisfaction with this choice of carburettor. 

Do not flinch at the fact that some sites refer to Japanese SUs ~ Hitachi licensed their carbs from SU and are very similar. All SUs work the same, and I find it telling that the Datsun folks have done a much a better job of understanding and presenting their knowledge of the best SU theory and practice than most of the British SU sites. (JMO). With that in mind, perhaps it should be little wonder that SU carbs have been too often misunderstood within our ranks.

I once read a little snippet in, of all places, a Bosch manual on electronic fuel injection systems. It made the point that of all normally asperated mechanical carburettors which preceded electronic fuel injection, only the SU came close to duplicating EFI's ability to follow the demand of an engine with precise fuel metering throughout the rpm range.  An interesting comment from an interesting source.