I have a 97 Heckler and have used it with 4-5 different forks, including Fox, RockShox, Pace and Marzocchi.
Also using a Ritchey external cup headset, but all of them cleared the downtube.
If you have a Chris King headset to swap in, they do a 3?mm extra high crown race in 1.1/8" which could do the trick.
Enjoy!!