I can help Tony Pignaloni with the request for rubber blocks for Ampico
motors.  Nowadays, there are countless dozens of rubber-like compounds
that can be used to mold new blocks.  I live in New York City and I go
to "The Compleat Sculptor" in lower Manhattan.  Their web site is
http://www.sculpt.com/   A quart of "Mold Max 30", catalog number
66S30A, is about $30.00 and is probably enough for two sets of 4 blocks.

An important thing to remember is that the blocks must contain a hard,
flat substance that is molded into the body of the block, or the steel
rod that goes inside will eventually push all the way through.  A small
piece of metal or wood will do.

Another thing to remember is that there are mold-making materials as
well as casting materials.  Depending on the job, a mold making
material can be used as the casting material.  For instance, the
product I recommended above is really a mold maker, but the rubber is
firm enough to be used as a casting material for making the motor
blocks.  The Smooth-On Company http://www.smooth-on.com/  makes most of
these compounds for stores like "The Compleat Sculptor" but the prices
are likely to be the same as found in stores.

This subject is basically an easy one to learn, but I am not going to
write pages of instructions since this information is easy to find.
Of course, I will be able to help with any questions you have.  Before
these compounds became readily available, the only way to make these
things short of an industrial vulcanizing process would be to obtain
blocks of rubber, freezing them with dry ice so they became rock hard,
and then drilling and machining them.

Randolph Herr