Albert help might be at hand here. The extract below was from a drift forum. Where I cant comment on the 2wd sierra stuff I can check out the 4wd stuff because I have two sets of 4wd hubs here. If the below is true that might be the best option. I will check them out for trail today and let you know. Its the negative trail that is wiping out the effect of the caster and causing the problems. Its a shame it was not noted when the cars were being developed because they could have mounted the rack behind the front axle and just reversed the hubs giving positive trail, but thats not where we are.
For drifting Sierras lack caster and lock, so I want to use 4WD front hubs as they give more caster angle than the 2WD hubs. I had them left over from when I broke the XR4x4 I had. I've already removed the CV joint innards.........
.......and to increase lock I want to get the hubs redrilled to change the location of the track rod end. Like this.......
.......although I want a tapered hole so I can use the OE track rod ends, instead of the bolt and rose jointed affair I'm the photo.
Using 4WD hubs means I must use the pinch bolt type track control arms (which I've also got) and the larger diameter 4WD dampers too (which I don't have).