I have a old 351w, with the old school V belt pulley system. How hard would it be to get a 6 groove serpentine belt system, with automatic belt tensioner? Any companies making a conversion kit?
To swap into what kind of car? Assuming a late model Mustang, you'd just use the brackets in the Mustang and be done, also using the reverse rotation water pump.
www.50resto has all the pulleys but they want big $$ for them. Try to find a salvage yard that has a 351 or 302 with the entire set up. Most should sell them all for much cheaper. Get the brackets for the accessories if you can.