need help identifying what cooling fan came on my bbc

[atowley]

Hi guys! I am working on an old rv, its a 1983 chevy class a with a 454. I built the engine and it dynoed at 400hp but i now need a fan to cool it. From what i have found online a 7 blade 19 inch mechanical fan is about the largest gm fan that was offered, but i cant find the application where they used these fans. Its part number 3999260. Thanks for the help! And if anyone has one that would work i certainly would be interested!