440 question

Ok the casting number on the side of my block which is black and so is my mates block is also black, anyway numbers are :2536430-6 12-6-1969 R/B F code
The difference is his has HP stamped into on the top close to the dizzy.So theirs no difference in the castings?no special mix when poring the block like wee were told? I did think it all was a bit ridiculous for the factory to do that.So the only difference between them and im not measuring penises here chaps but like you guys say cam,heads,intake,crank?