Type 3 Porsche Wheel/Suspension Help

[jaymonz]

Hello all,
I have been lurking on the forums for awhile now...really haven't had a question I couldn't find an answer to until now...I have a '70 square with a swing axle setup (I don't know how that happened, the chassis seems original to me). At any rate, I have been fortunate enough to come across a set of Porsche Turbo Twist 2 wheels. The fronts are 18" x 8" with a 50et. The rears are 18" x 11" with a 45et. I know that I'm going to have to convert from swing to IRS and probably narrowed IRS at that. I need some insight into what I should do first to make the rears fit. I've done searches but couldn't find the exact answer as it relates to type 3's. Thanks
Jaymonz