Downey is correct, mounting all three points tight will cause failure somewhere, I learned this and luckily only lost 1 of the two bolt journals on the bell house on pass side. I now have the bellhouse mounts on soft bushings and they dont rest on them they sort of hover and it does let the...
Once you place the frame side tab on pass side, the horizontal part of tab, or shelf if you will, protrudes from frame toward center and has a large hole which the bushing has a shouldered index part that fits in big hole, the remaining portion of tab that extends beyond hole toward center...
I have your same exact set up for 20 + years. FWIW setting all 6 is tricky. The mid mounts on the bell housing will work loose periodically and if the rear bushings are not right or fail it can cause the ears on the bell house to break, not the end of the world. Set the motor, bolt everything...