EARLY LITTLEJOHNS HAVE A DEFECT WHEN IT COMES TO METRIC THREADS ( NOT ALL EARLY ONES) ONLY THOSE WITH 2 5/8 INCHES BETWEEN A/B STUD CENTRES. THE METRIC CHANGE GEAR ON B CLASHES WITH REVERSE TUMBLER ON REAR OF A SEE PICTURES FOR MOD.THE GEARS SHOWN ARE FROM B & C THE SPACERS GO ON STUBS B & C BEFORE FITTING THE GEARS. ASK!!