You said you put it on the wheelhouses, did you do that in the engine bay and the trunk and is it sitting on top or on the inside? I know some companies make a spray on to coat the inner wheelwells to make it quieter
I put it on the inside (Trunk side) of the rear wheelhouses. In a fastback barracuda with the rear pales out you have pretty good access. Did not do anything on the wheel side of the wheelhouses.