Narrowed C4 rear suspension HELP

I have a 1974 Triumph TR6, 1992 5.0 HO V8 swap, AOD trany, converted to carbs completed May 04. ( she will snap your neck in all gears! What a rush!)

I'm running the stock IRS but I know that will not last long! Back in Nov.04, a complete 1984 C4 rear suspension fell in my lap, so
I'm making plans to narrow and install.

The C4 is 60" wide, the TR6 is 50", I plan on using 2" wheel adapters to mate the Chevy pattern to my Panasport wheels, so I think I'm looking at 7" per side.

My question, is it possible to narrow the C4 that much?

My local hotrod club members say to sell the half-shafts and get custom steele half-shafts made. Any thoughts?

Should I try and get a custom rear spring made or go with coils?

My goal is to have a stock looking TR6, performance road car, with modern features. A sleeper that I can enjoy on the back roads of WV, OH, and PA.

Thanks for any info or leads.

Thanks for the leads! The book is on order. I'll start the process of looking for another frame to work with the build process. ( She is running now and it's almost cruise season)

Anyone know of any shops in my area that might do Alum.welding? (Pittsburgh,PA)