FD 5000-6610 Engine number

[russn1949]

FD 5000-6610 Engine number
what is the meaning of the T numbers (T1,T2,T3,T5,T7) stamped on the right side of the engine? Newer engines are webbed and have no T number. Thanks

 

[whodat526]

the t numbers really or a casting number and just vagely tells you the year model and the bore of the engine