Whats the max I can narrow this rearend?

[DRJDVM's '69]

Right now I have a stock rearend that I'm using for mock up etc. The plan is to get my tires and rims set up the way I want.... 20x12 with a 335 in the rear, shooting for about 4.5 inches of lip on the wheel.... then measure for my rearend after I get my rims and tires EXACTLY where I want them.

The plan is a custom Dana 60, big Torino bearing, Wilwood brakes......

So how much more narrow of a rearend do you think I could do and still have the clearence I need for the U-bolts, brackets, brakes etc etc?

I'm not planning on maxing out how narrow I could go.....only get a rough idea on how much I have to work with before I may run into issues. That will allow me to get my BS in the ballpark and then fine tune everything when I measure for the rearend. I've never done a custom rearend, so I dont want to pick a BS for the rims that will force me to go too short on the rearend width etc.

In the pix, from outside edge of axel flange to U-bolts is 8 inches...