Primary gear and idler for 3 & 4 Synchro

[Minicooper1964]

Ok I have a question - will the 1275 engine 4 synchro primary and idler gears fit a 1275 engine with a 3 synchro 333 box ?

[minibitz]

Yes, providing the idler and primary are pre A+.

[Minicooper1964]

Hi Minibitz thanks for fast response. I have a drop set from a 4 synchro box ready to fit so how can I tell if the set are pre A + ?

[Spider]

Pre A+ Primary Gear will have 24 teeth
A+ Primary Gear has 29 or 30 teeth

Pre A+ Idlers have 31 teeth and 3/4" Shaft
A+ Idlers have 37 teeth and 7/8" Shaft

There's also the Pre-A+ Auto Idlers. These too have 37 teeth but 3/4" shaft.