47-55.1 Last minute build issues, camaro clip

[atotalnincompoop]

I'm at the tail end of building my 55 gmc. I have a camaro clip and rack and pinion setup from a chrysler 300. It's all done and looking good.
I was excited to order a set of detroit steel wheels, I measured and calculated what I needed several times. Once I was confident in my offset requirements, I called and ordered my wheels, the fronts were to be 18x8 with 5" back space, I was going to order 225 tires. The truck is bagged and rides low. My salesperson told me to run 245 tires and get 4.5" back space. She said that would work better for me. I figured they knew better to me...that was my first mistake.
My wheels arrived, I took them to my painter and got them painted, then had my 245 tires put on. Upon installing them on my truck they are too wide and rub the inside of the front fenders. I can't turn at all.

Here is my question...I understand that I can change my truck width by swapping out my control arms to 78-87 g body (monte carlo, regal, etc) control arms. Adjusting my rack setup width is not an issue. I did a little research in the archives about doing this, have any of you guys done or seen this done? What do I need and what do I need to know?
It's too late to switch clips and I'm not paying $1000 for the heidts or fatman narrowed control arms
Any input would be appreciated
Greg