Well anyway, the point is still a valid one. I'll see if I can remember some other aircraft with a TSIO-520. The A36TC and B36TC spring to mind, and they suffered from poor reliability too, until the cooling problems were fixed in later B36TC's.
The TSIO-520 is specific to the following aircraft:
Beech 58P
Beech F33; V35
Beech A36
Cessna T188C; T188C/A1
Cessna TU206F; TU206G; U206G
Cessna T207A
Cessna 210N; T210G; T210N; T210L; P210N; T210M
Cessna 310R; T310R
Cessna 320D
Cessna 340 & 340A
Cessna 401; 401A; 401B;
Cessna 402; 402A; 402B;402C;
Cessna 414; 414A; 414/A1
PA-46-310P
DF.