I am looking at my 4th revision on my custom spindle. I just duplicated the F-Body geometry though and haven't looked at making it taller because at the time it didn't seem like anyone was worried about the stock spindle height. I started with a bolt on setup for a stock disk brake spindle to use the 4 piston Brembo's and 14.2" rotors from a Challenger so I based the custom updright around that setup. I originally tried to use the Challenger front hubs but bought (and then returned) 2 or 3 replacement hubs to check the wheel bolt pattern and found they all used the 115mm bolt circle and wasn't going to go down that road. So I stole the S550 hub idea off the spindles RideTech introduced.
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It's all just flat plates welded together and bolts, but I have been trying to come up with a better system to set the hub location. The distance from the hub to the caliper ears is pretty important and the plates have some tolerance on the thickness that can stack and upset things a little. But with flat plates and laser cutting from SendCutSend, I think it was only $500 for a pair but it's been awhile since I did up a quote. The biggest issue is the UBJ mount. I was planning a solid 1" thick bar and a washer to duplicate the stock spindle thickness there and it would require the taper to be reamed into it. More work to do there as well.
The real reason I started look at this was that I wanted to run ABS wheel speed sensors. So this setup has provisions to mount LX/LC sensors.
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This most recent go round, I spent some time thinking about brake packages. I like the OEM stuff just because it seems like you can get parts for much cheaper than the aftermarket Baer or Wilwood stuff. Maybe it isn't as good, but hopefully good enough. I was going to jump up to the S550 6 piston 15" rotor package as my 18" wheel should still fit, but I decided I didn't want to put 34# rotors on the car. So I plan to stick to ~14" setups. The S197 4 piston setup seems like a nice package, but the S550 4 piston setup is junk. The only one I didn't look at was the Camaro 1LE stuff, but a Corvette hub, those brakes and a swap to a GM bolt pattern might not be a bad option.
One of the things I looked at was scrub radius. The stock spindle appears to have about a 7 degree SAI and with my setup, I am getting about 2.45" of scrub radius. I think that could be better. Note that my custom upright results in the surface the wheel bolts to being in some compared to the stock spindle by maybe 3/8" or so. Changing the UBJ location and SAI to reduce the scrub radius would require shorter UCA's or the aftermarket adjustable ones. So that's up in the air, too.
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Another discovery is that the LBJ isn't centered on the spindle and there is about 0.5 degrees of negative caster built into the stock setup.
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I've thought about moving the UBJ hole back about 1" as that would create about 6 degrees of built in positive caster and would keep the wheel more centered in the wheel opening. But I haven't figured out if I will try it, partly because I think I would have to move the caliper to the front of the upright and I'm not sure that won't create issues with the sway bar. I think it would be a better location in the end, just not sure it wouldn't snowball into a custom swaybar like Joe just built.