casting numbers

Can anyone tell me what the following block casting number is from: 12561358?

I just found out my heads are 862s and those are from 4.8L. I'm nervous my block is also from a 4.8L. Thanks in advance!!

is it an aluminum or cast iron block? 4.8/5.3 are cast -5.7 aluminum

4.8 and 5.3 blocks are the same the only thing diffrent is the crank. I think there the same heads too

This is a cast block. Then without opening up the engine, I won't know what I have...

So the 4.8 and 5.3 use the same heads and block. The 6.0 uses the same crank as a 5.3?

I think so i know that the 5.7 use the same crank. im almost sure they use the same crank just the bore size is diffrent