[TR] Spitfire Mk III Engine Interchangeability Pre-71?

[Wayne Lee]

Hi List,
     I seen an Engine For Sale that when reading the description raised some
questions.
The 1300 Engine was described as fitting OEM 71-74, but that it would fit all
Spitfire
Frames 71-80.
   I wasn't aware that the earlier 1300's were the only Engine to fit into a
pre-71 MK III.
I understand that You can basically fit anything into anything. But what's the
difference?
I've seen a few 1500's put into MK III's. Is a special mount needed?
Cheers,
Wayne
Douglas, MA
64 TR4
69 Spitfire
75 TR6