1966 T Bird vin

What can you guys tell me about this car , it's a 66 bird

What the guy is telling me is it's a 428/ automatic hears the vin number
6Y870118413

It's got a FE block but I cant tell a 390 from a 428

Aney help would be great
thank you
FATS

Hi-
The ID says its a 66 2 door landau (no rear quarter window and it has a vinyl roof cover). The "O" should be a "Q" and means it originally had a 428. The rest of the numbers are the Ford sequence or ID number.
Its very hard to tell a 390 from a 428 without checking inside the engine itself. After all these years the engine could have been replaced with anything from a 352 to another 428.
Look for a metal ID tag near the coil, it would have further engine info. It still could be wrong if the engine was replaced.
If it looks like its never been removed it could be the right tag.

Another way to tell an early 428 is to look at the balancer on the front of the engine. A 428 will have a balance weight as part of the balancer assembly. It could be a seperate part or could be an integral part of the balancer. IF it has no weight it is a 390 or smaller engine.

Hope this information can help you!