I recently replaced the distributor in my Ford F-150 400eng. with a
rebuilt from the local parts store.  I have poor eyesight, and could
not read the timing marks real well, so I timed it "by ear".  The
other day a friend came to visit from out of town.  He's a retired
mechanic.  I told him the old truck still had a miss. He said he would
set the timing for me using the timing light.  He took off the
distributor cap and immediately said there is supposed to be a felt
thing in the center of the shaft, under the rotor.  He said it's not
there.  

I know what he means, I have seen them in other distributors.  I
always thought they were there for lubrication of the shaft, but he
said the real reason they are there is to prevent a spark from popping
thru the rotor and shooting down the shaft hole.  I thought he was
"pulling my leg", and laughed.  He said he is serious....

I trust this guy, and he was a very good mechanic.  But this sounds
real weird.  Is this for real, or is he really pulling my leg?

In the meantime, the parts store said they dont sell them separately,
and do not know how to get them.....

Anyone?

Thanks

5000HP