British Auto Service in Milwaukee, WI might be worth a try. They work on obscure stuff (steering rack for a Rover P5) so they may be what you need. Number is (414) 273-0007. Nice guys, Craig and John are the owners. If not, try Sportscar Services in Mequon, WI. (262)238-1133, speak to Bill. Good luck, let me know how you get on.
Steve