I've noticed since day one of my installation of the rebuilt motor in my 90
GL, that upon start up, the torque of the engine first starting moves so
much that the Stebro muffler clanks against the body smewhere and sounds
like the engine is knocking initally.

  Bought new rear engine mounts from Ken W. so that shouldn't be the
problem(installed at overhaul time) and within the previous year replaced
the front tranny mount with an original VW part.  Last weekend, I was under
the car briefly and grabbed the  tailpipe and was amazed at how much motion
I generated just pulling up and down on the pipe.  I could even see the
rotation in the transmission mount up front.

I've never had any problems from parts from Ken in the past and the front
mount wouldn't wear out in a year(not sure the original mount ws bad).
Could it be the "massive" increase in torque from the "half Lilly" Boston
Bob engine?  I don't think so.  This motor has done this since day
one.  Another thought is the clearances of the Stebro muffler may have
something to do with the noise, and no, I haven't had the wife drive with
me huddled over an open back hatch to see how mucvh the motor moves during
driving.

Anyone out there have a handle on how much the motor should move
around.  It appears to be difficult to discern whether or not the rear
mounts may have sheared their bonds. These ere German made mounts if memory
serves.  Any thoughts appreciated as always.

Dimwitted Moose and Flying Squirrel