Reformed ford guy needs SB Chevy ID help!

Hi. Not only am I new to the site but after 30 years of Hot Rodding Fords, I just bought my first Chevy. I am the proud papa of a 1951 Styleline Convertible. It has a Power rack front end. Auto trans. A 10 bolt rear. And I don't know what engine! All the numbers off the block don't jive. The Suffix is F0731ID. ('66 HP 327) The casting # is 3789985 (could only find a "35" that denotes a 283) and the date code is G282 (1962)
Can anybody make sense of this? I sure could use some advice before I order any cool go-fast parts.
Thanks.

I had a helper check the numbers as well and it is a the questionable casting number is a '3' which means it's a 283. The date code is for 1962
BUT! the suffix is a 1966 HP 327.
All of these numbers are off of the block. I don't get it?

someone told me that the casting and date codes are molded in when the block is cast. Then when the engine is actually machined and built, they put the suffix code in.(cast in '62 built in '66) Anyone ever hear of that?