I take you mean front and rear including all the leaf spring mounts etc. Paykel Engineering Supplies here in Lower Hutt sell a product called Lurathane which is a machinable urethane. So if you know a machinist they can turn some up for you..I think it comes in different hardnesses too. For the spring shackles you could use alloy for the bushes...race only of course. Otherwise George Stocks in Auckland should have urethane bushes available.