I got a set for one of my Pacers a number of years back, but the last
time I talked to them, they said that they no longer do leaf
springs. I need a set for another Pacer, looked at JC Whitney, but
also found General Spring of Kansas City
<http://www.generalspringkc.com>. I haven't used them, but they list
dimensions for both the early and late Pacer springs, so they seem to
know what they are doing. Another well-known source for leaf springs
is Eaton Detroit Spring <http://www.eatonsprings.com>, but they tend
to be pricey.
General Spring lists the 1964-69 American spring at $149 each. They
also do custom springs, so you can tell them what you are doing and
they can make a recommendation.
--Glen