The 123\MG-4-R-V is designed especially for the MGA and MGB.
All the advance-curves, that were ever specified for these cars, are integrated into this product.
For MGC see 123\GB-6-R-V. The unit offers a maximum total of 16 advance-curves to be selected by the end-user.
Please take a look in the curve table for available advance curves.
MG – 4 – R – V = MG stands for the 123ignition type
MG – 4 – R – V = 4 stands for the number of cylinders
MG – 4 – R – V = R stands for straight distributor cap
MG – 4 – R – V = V stands for vacuum advance