Re: The "W" Block
 

If I could find a "letter" block I would use that but I have used regular 59 blocks and got away with it.

Re: The "W" Block
 

My L block is at 3.4050" (3 3/8" + .030) after the required boring and, according to the sonic testing, still has a lot of meat left in the bore.

That said, we went with Ross pistons and they had to be "custom" made. This did add appropriately $200 to the price. No one said building a flat head is cheap, though. LOL!

Re: The "W" Block
 

We used to bore blocks for our race cars, and kept increasing the size until we found a block that wouldn't blow a sand hole. That was many years ago when more blocks could be had from the local "junk yard". The "enbloc" sand casting process used by Ford resulted in a very high rejection rate at the factory due to "core shift" during casting. Minor defects could sometimes be repaired by sleeving, but this defeated the original aim of all cylinders being equal. At our shop we do lots of boring, but haven't found a reliable test for cylinder wall thickness in old blocks.

Re: The "W" Block
 

Yes, "reliable" is the key word here. You can sonic test a cylinder in 50 places and still miss a sand hole or core shift flaw.
Eventually, vintage racing will die or they will have to let after market blocks in.

Re: The "W" Block
 

Just an anecdotal observation based on the several 59L blocks that I have in use and on hand, none of them have any visible cracks. I know that the old flathead racers all coveted 59 L, X, Y, Z blocks. (as well as 39-41 Merc./truck blocks). These guys were not dumb, they must have had a reason for this.