M code engine ID

[scottsMcode]

I have a 69 GTS factory M code. I have owned the car since 1982. My dumb question is how do I know if the motor is original to the car? The block is a D code 1968 cast in October. The car was built 2/14/69. And we all know the goofy history of these cars. Any help is appreciated.

 

[racerkilla]

im pretty sure the engine is cast year before

ex 71 car has 70 engine code.

your being oct was also late 68.

not 100 percent

 

[Alaskan_TA]

D is the series (model year) 1968

A '69 model year block would have an E.

Some '68 engines have the VIN stamped on top of the bell flange at the rear of the engine.

'69 engines will have it on the passenger side of the block, down low near the oil pan rail.