Since 1989 this book (back in 1989 1. edition - now 3. edition) has been more or less my bible. Lots of illustrations and photos with well written text explaning what to do and NOT to do, to make the A Series engine develop more power and/or better economy/mileage. All the practical tips is supported/documented by serious testing - and the background theory!.
Especially interesting is:
the camshafts chapter (contains both test results proving the Scatter Pattern concepts potential and the reason why it works/theory behind)
the cylinder head chapter (including the latest 7 head from AKM Racing in Denmark)
the Blocks, Cranks, Rods & Piston chapter (which type of block to use for boring to 73.5 mm, which pistons, where to find good rods and how to lightening them safely)
and I could carry on - In short:
A MUST FOR ANYONE WITH INTEREST IN TUNING THE BL'S A-SERIES ENGINE - GREAT VALUE FOR MONEY, AVOID DOING THE SAME MISTAKES OTHERS HAS DONE!