Not sure if this helps, but my Tahoe has parts from a Beltech 4/6 drop. I have Belltech spindles. Wheels are 20x8 with 5" of backspacing. Front tires are 275-40 R20 Toyo Proxes. The wildcard on my setup is the front springs. They are from a 69 big block Camaro with some coils cut off. I have no rubbing on the front fenders or a-arms and I'm pretty sure the fenders have not been massaged. Can check in the morning. I know my rear fender well opening have been rolled.
With the cutting of the coils I am not exacly sure how much drop is up front. I know it's lower than 4" though. When I put the new front tires on the front end sat too high with the Belltech springs. I cut too much off of those and that's how I ended up with the Camaro springs. Looking at the attached picture it looks like I could lose another inch.
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