Does anyone know for sure if the rear motor mounts are the same for a 47 flathead straight 6 and 8?
I need one and all I can find say for 8cyl. they look the same in pics.
I think they should be the same. Motors are basically the same, one is just 2 cyl. longer.

 

I can't answer your question, but did you check Fusick and Kanter for the motor mounts?

https://www.fusickautomotiveproducts.com/

https://www.kanter.com/