one easy way to make the extenders is to get 2 exhaust phlanges (chevy SBC I believe). Cut a section of thick wall tube to length, weld it up.
The exhaust flanges are just the perfect size to mate up to the strut mounts.
So, 4 flanges, 2 1.5" lengths of tube (I'd suggest 1/4" wall), 6 bolts and nylocks and then add a pound or so of wire.