Triumph TR2 Service Instructions Manual page 367

FOREWORD
Certain modifications have been incorporated in the
TR3 models and have been made w i t h a view to
enhancing its appearance and performance.
Whilst the general specification of the TR3 agrees very
largely with that for the earlier models, there are certain
differences which are set out in this Supplement.
The nature of the modifications made to the later model
cannot be easily incorporated in the earlier models, nor
is it the intention of The Standard Motor Company
(1959) Limited that they should.