[Jrainman]

You can use your same water pump and pullys from that 350 with no issues

I would say they are not notorious for over heating falure ,but they can be prone to over heating because the 400 block has siamse cylinder bore, witch required the heads to be drilled for steam relief , so they are one off heads on the 400 and reqiure correct parts and gaskets , they were never made for performance but from 1971- 1976 they used them in a lot of cars and trucks , I just picked up a 71 impala with a stock 265 HP 400 in it, the car was shot but the low miledge 400 turned rite over and it was sitting for a lot of years ,not that I am a fan of them but if put together rite they will run good.