When tuning any car fitted with single or twin SU carburettors it is essential to get the correct needle for your size engine and engine modifications such as head work and modified camshafts. This book will give you the diameter measurement of each needle from idle up to full throttle, and what stage the needle changes sizes. This comprehensive book contains over 700 SU needle profiles for the following categories of fixed needles to suit .090″, .100″, .125″ & 3/16″ diameter jets.  Spring loaded or floating needles for .090″ & .100″ diameter jets.

example from the booklet:  Dimensions of a fixed DZ needle to suit a 0.090″ jet are as follows.

1  =  .089  dashpot end  of needle (idle)

 2  =  .085

3  =  .0827

 4  =  .0795

 5  =  .077

 6  =  .0745  middle of needle (midrange)

 7  =  .0715

 8  =  .070

 9  =  .0685

10  =  .067

 11  =  .0655

12  =  .064

13  =  .0625   tip of needle (full throttle)