17" wheel offset '67 barracuda

I am in the process of building '67 barracuda fairly similar to this barracuda featured at this link.

http://www.popularhotrodding.com/features/0602phr_1967_plymouth_barracuda_fastback/index.html

My car though is built with factory/aftermarket parts such as a '73 k-member and bigger torsion bars and leafs and front and rear sway-bars and disks. What I have been having problems with is the proper offset for the front. I am looking to use 245-45-17 tires on 8" or 7"-17" wheels the offsets I have available are 20mm (5 1/4" bs) for the 8" and 40mm (5 9/16" bs) for the 7" wheels. Has anybody used this combanation? Or any thing simaler without rubbing the fenders or suspension? I realy do not want to run spacers or cut and modify the fenders. Thanks-Bill