I need a Block casting ID verified please

I'm heading over to pick up a /6 tomorrow and need a quick casting ID. Everything that I can find says that it's '66 225 according to the casting but there is also an upside down 170 cast into the as well. Just want to be sure here.

The casting is 2463430-6, but as I mentioned there is also an upside down 170

Thanks

my book shows two numbers. 2463430 applys to 1961-74 198 and 225 6 cylinders. 2463430-1 is for 225 engines of the same years. your -6 casting number does not show in my books but that doesent mean they are not exact. the casting date on the block will help a lot and so will the original colour of the engine.
blue - most likely a 225
red - either 198 or 225
yellow - either 198 or 170 (most likely)
if the casting date is there most built in the 70's are 225. hope this helps a bit.
my bet is the -6 stands for 1976 and the engine is a 225.

this is what I'm seeing....

G/RG SLANT-6 BLOCKS
CASTING # C.I.D. YEAR GROUP
2202843 170 G
2205630 170 G
2264478 170 G
2463230 170 1965 G
--- 198 G
2202857 225 RG
2205528 225 RG
2463430 225 1966 RG
2806830 225 RG

http://www.yearone.com/updatedsinglepages/Id_info/mopar/mopar%20casting%20numbers/castingnumbers.html

My stock motor in my 64 is yellow and I have identified it by castings that its a 225.

I just don't understand the upside down 170 on the one I am picking up

but thihs one shows sevral years

http://www.mopar1.us/casting.html

found this...

The 2 most common RGFC blocks have the casting numbers 2463430 (60 – 67 forged crank "early" with 3 freeze plugs & red paint) and 2806830 (68 – 75 forged crank "late" with 5 freeze plugs & blue paint). These casting numbers are followed by a dash and a 1 or 2 digit number (-XX). The dash number is a "link" to the casting pattern equipment used to produce that casting.


http://www.slantsix.org/articles/dutra-blocks/slant-blocks.htm

still nothing on the 170 tho

I had 2 yellow 225's (1964) and 1 blue 170 (1968). My best guess is to also check the head #s weather its a 225 or 170, If it looks unmolested original. Im not sure on block numbers.