There is no small block chevy head with the casting numbers you listed, all the heads from the 60`s started with a 3, but a 3 is easily mistaken for a 8, also I can`t find any record of a 484 casting. look closer at the numbers, you may need to spray some cleaner on them and do some scraping to see them better. To tell you further of this block, look on the passengers side of the blocks deck, on there should be the suffix code, it should look something like this: DRD as a example. post the suffix code and we can tell you what it came out of and it`s power rating. If you`ll look on the back of the bell housing, you`ll also find the date casting, it`ll look something like this example: A 4 5
A = January 4 = 4th 5 = 1965.
The months start with a letter, A is january, B is febuary and so on.