Front tire sizes?

My lowered 68 Barracuda
wears 235/60-14s (25.1"tall) on 7.5" rims ( I guess wheels to you yanks) with about a near-zero offset. (IIRC 3.75 bs)..
The K-member is about 5.75 to 6.0 off the deck, and car sits about level with a minimal rake.
She wears; KH brakes, 1.03 bars, a fat swaybar, and ancient 3-way Munroes. And I sucked the LCAs ahead just a tad in an effort to find some caster.
My K has been down to 5.5, and it still drove fine. But I kept snagging the Milodon Roadrace pan that hangs an inch lower. I finally made a nice skid-plate for it and that solved the carnage on the pan. No more compensation for speed-bumps; she just hammers over them.
Check your backspace; I bet that's where you will find the problem. Either there or in the ride-height.
With taller tires on wider 15"rims, the back space needs to be greater than 3.5/3.75, and/or the front corners of the wheel-openings trimmed, and/or the tops of the openings rolled out. Yes, as mentioned, you can push the un-trimmed corners out with the tin-struts, but I'm not a fan of that look.
The correct maximum wheel-offset is required to keep the back of the tire from rubbing on the frame. Your three/four contact points vary slightly with suspension travel. You cannot move the frame, nor the strut-rod, so those are your limiters, Everything else can be moved.