I know this is a question that has been asked but i need more explanation. So i am putting a 65 289 in a 67 coupe, I have the frame mounts and have tryed to instal them and they did not want to fit, why could this be? Also will the engine mounts fit to any of the frame mount brackets?

 

I ordered some frame mounts for my 65 to convert from a 6 cyl. They wouldn't fit the new (65) mounts I ordered for the engine. I found out the frame mounts were different and I ordered some engine mounts for a later 67 or so and they fit the frame mounts fine. So my answer is, there was apparently a difference in 65 and 66 or 67 and later.