If it was me I'd a) check all of the other front spring hangers and see if one of them will work (i.e. Dodge ,Plymouth, superstock and non-SS).

Plan b) would be to buy the 2" longer SS front hangers and drill them for 1"and trim excess. I have a 29.5x10.50 in my '66 Charger and other than the above my only tricks are to use a 68-69 width Dana and replace the rear shackles with sliders.

AR Engineering makes really nice front spring hangers if you didn't know about them. I bought several sets from FirmFeel during mock up.