There are other standards for the build over an above the MOT there are the Motor sport Association Rules (MSA) for which track racing cars need to comply then there are the 750 motorclub specific rules over and above these .
You need to get your hands on an MSA blue book (the book of rules) if you've not already got a licence its worth sending off for a licence pack, it will cost you about £45 I think, but you will need it anyway so that you can apply for your licence once you have doen your ARDS test. This book has all of the motorsport regs, however you are best to read the specific 750 motorclub regs first as these will point you in the right direction for your build, they are what I used when I built mine in 2006.
MSA web site address is
www.msauk.org follow the licence application link
750 motorclub website is
www.750mc.co.uk follow the locost link.
Its also a good idea to get along to a few meetings and chat to some of the guys and take pictures which is what i did while building mine as it will point you in the direction of what you do and dont need most of the guys are willing to talk and are very helpful.
Hope this helps
Regards
Alastair Locost 51