My 351 c reinforcment casting marks....?

[td71mach1]

h
Here recently i researched some characteristics of my engine block. Apparently these blocks were experiencing cracks in the corners early on, so ford starting casting them with the "Y" and "X" 's in the corners to reinforce and stop these cracking problems. In my limited time researching i have not yet seen a block with the reinforcment casing marks all the wat across from end to end like this one. It is a 2 bolt main.....rrrrr. lol. i believe the casting reads 7/23/1973. My question is, is this a good thing, or otherwise. were ther problems continuing into 73 ?

 

[mjlan]

I have heard two stories: one is that 'X's and 'Y's were used to repair tooling when it got old and worn and the other that the addition of the letters helped with material flow in the cores in the areas they were added during casting. I guess two ways of saying the same thing...

If you are concerned that this somehow weakens the block, find another one.

If there is some truth to the worn out tooling tale then maybe a '70 or '71 casting won't have these marks?

 

[Stanglover]

Just for the heck of it, here is a pic of a 1970 N block I had that dumb ass sold.
There is no sign of "casting core pattern repair". The "N" block had the oil drain holes at the back until removed for 71 that had a crude hole at the front.

The X's are probably a core pattern repair and do not actually mean "X". The "Y" are probably a foundry marking of some sort to indicate the core has been repaired. That would be my guess.

 

[Steve73QMach1]

I had the X's and Y's and a few V's on my original 1973 Mach 1 351C 4V block, 4 bolt mains. The car was a July 1973 build. Here are a few photos from before the engine rebuild. These were only in the corners.