In the July edition of Safety Fast and there was an interesting article on Syd Enever's Tuning Information Memo's. Syd would have been Chief Engineer at Abingdon during the production of the 6 cyl cars which took place there.
Whilst there are Special Tuning Booklets for the MG cars, I have never seen any for the Big Healeys, or perhaps I just haven't come across them.
However back to the story ... Over the 17 years at Abingdon, Syd wrote 48 Tuning Information Memo's. These were apparently internal documents and not for circulation outside of BMC, but in some cases were the basis for the Special Tuning Booklets.
Anyhow some of these TIM's relate to the Healey Sprite, 100/6 and 3000 models and are shown in the following Threads.