Unknown GM Casting code

I recently purchased what I believe is a 1960 or 1962 283 or 327 motor. The engine suffix code displays 2100007 and F0602RF. The "RF" states a 327, the guy I bought it from thought it was a 283. What is weird is the casting number on the left rear of the block..GM 0-193457, which doesn't match up with any casting # I've seen. Can you help with this casting number? The casting date is L90. The engine also has another weird side to it. It has the GM aluminum intake #3731394 with the 2 Carter 4 bbls. The heads are 3731554 and it has the aluminum Corvette valve covers. The blow shield is a 373#, so is the water pump and flywheel. It seems the top end is from 1957. There are no swirl marks on the front suffix pad to indicate a changed suffix code, I have no idea what 0-193457 means. That casting # is plain as day to read and there is absolutely no mistake in reading it, can't wait to hear the feedback on this one, if pics are needed I can supply.
Bart

3731554 57-62 283 heads http://www.mortec.com/castnum.htm

1986-57 3731394 283 8 al WCFB Y/225hp, 2nd design http://www.nastyz28.com/sbcmenu.html

for the block...not as sure on this, but found
1957 F 283 Powerglide - 2 cars & Vette to refer to the first character (F) http://www.nastyz28.com/sbchevy/spcode5.html

if we try the RF at the end we get
1962 RF 327 manual trans. 360 FI Vette
http://www.nastyz28.com/sbchevy/spcode6.html

The GM 0-193457 - partial VIN number??

Anyone else got some thoughts?

Thanks Screamer63, I figured the top end was a late 50's 283, and I'm hoping the block was the 327/360 with 11:1 pistons, maybe I'll get some more replys.

Some of the folks here (streets for one) has the books for interchange numbers and have been around long enough to have seen 1957. I use the 'net, and not all the info there is 100% accurate...and i'm not a chebby guy so that makes it one step tougher. But hey, i tried!