I have owned my 87 Graduate for about 5 years and have been plagued by the thumping while starting off in 1st gear. After replacing the transmission mout bushing, the carrier bearing rubber, the bushings in the rear trunion(?), the guibo(?) and reading numerous posts from other BB members with the same problem I decided to try something a little different. I removed the plate spanning the frame rails that the transmission mount bushing attaches to. I then completely filled the voids in the bushing with silicone caulk. Put it in from both sides to make sure it was filled. Let it cure for a day and then re-installed the mounting support. I realize this is probably a temporary solution but was just trying to see if it made a difference. It has been 2 months now and not a single thump. Taking off straight ahead, turning left or right, lots of throttle or just a slow rolling start, not one thump. I have not tried a 4 grand and dump the clutch start and am not planning to, but in all other instances the thumping is gone.