Another thought came to mind - and again I got this from the Duraburb video ( you might want to go search that out): If I remember correctly Duraburb said that the Suburban 3500 had the "new" style 8 lug circle of 180mm or whatever it is. The "old" lug circle was like 8x 6.5" or something like that. That *might* mean that the upper A-arms are indeed different than anything else because they're adapting from the holdover 2500 frame - to the spindles that work with hubs for the 8x180mm bolt circle or something like that. I don't know - I'm just guessing. But - again - that might not mean that the upper A-arms are actually any different than say A-arms from the earlier 2500 Suburban/Yukon/Sierra/Silverado - it could just be that the ball joint is different than the "old" ball joint - so the A-arm is the same - but the ball joint is different. Again - don't know - I'm just guessing.
What you probably need to do is take some measurements or match up your upper A-arms - with an A-arm from an older truck - and see if they're the same. I might have my old one's still hanging around somewhere - I'd have to go look. You might also be able to get some measurements from a place like Cognito - to see if they'd match up. Sometimes places like that are willing to work with you - just because it gives them info they can apply towards their product line.
