We have been offering the Ferrari community custom harmonic balancers for 15 years now, designed engineered and built in the USA for Ferrari 308/328/Mondial/F40/288 GTO 
This proven design is used from bone stock engines to up to 750 HP version engines that we have built. These are a direct replacement part with options such as a custom 60-2 or 24 tooth trigger wheel or even as custom as a 15th tooth wheel pictured on my Personal " Its only Money NFF 4 liter engine". Call us for your custom version. Standard replacement Dampners start at $899.00

Options 

60 minus 2 tooth trigger wheel add on $ 120.00

Modern 5 ribbed belt design pulley (below) for Water pump and dampner ( 2 pieces) $299.00