I have a 68 chevy truck that had a small block and i am swaping in a 396 big block. I installed the big block frame mounts which seem to have moved the motor forward an a couple inches and now the motor does not rest on the rear cross member. I tried to move it forward but there are no holes in the frame to bolt it back up. I was wondering if there is a special cross member for big block trucks or if you have to modify the cross member to work. Any infromation would be appreicated.