We are in the process of putting a 390 in a 77 F150 custom 4x4 with stock truck 4 speed. We pulled a 302 out of it but the truck had a 351M from the factory. I have motor mount perches out a 76 4x4 390 truck and they only line up with 2 forward bolts on the inside of the frame (upper coil spring mount) and only the forward bolt hole on the top of the frame. We need some direction and this forum is the best place to find it. Surely someone here has done this. We would really appreciate your input. Thank you Denis