[Berg]

If you already have a beefy 3 core with the 4 bolt top plate you should be good on the rad. You should have a long water pump. I believe that the only year that could have had both long and short water pump from GM on Chevelles was a 1969. 1970-up should be a LWP. As far as the fan goes, the aftermarket kits have 7 blade fans and from my memory it looks just like the fans on both the big block and small block cars. They list it aftermarket as the same fan and clutch but i'm almost positive the LS6 and L78 cars had a special clutch on them. I think AC clutches were different too. They also come in thermostat or non-thermostat versions. You SHOULD be able to reuse your original fan but being it is only a 4 blade and direct drive I'd spring for either a thermostat clutch fan or a flex fan and spacer. Really the only big expense you'll have will be the headers/manifolds and modifying the collectors or engine pipes to fit the BBC. Front springs could be swapped out if you don't like the way the car handles. It wouldn't be a bad idea since the added weight may make it handle different. I personally don't feel that big of a difference.