Stephen - all the regular vendors have the repro factory front V8 mounts for 55-59,
like this, left in the pic bolts to existing holes in the front cross member, other brackets fit existing holes in the front of the block, on earlier blocks anyway, later you might hafta drill/tap a couple yourself
the one you link there is the 'universal aftermarket' mount, the original style don't clutter under the oil pan, work a treat on mine, just like the general made'em
Bill
