Not all FT blocks have the same core. The later ones do have the triangle cooling jacket like the 428s. Early ones do not. The reverse 105 blocks have that also. Some FT do have sand scratches such as C, CX, and CI. I would look for those if trying for the best choice to do this, but still a gamble. It's my opinion and it's just that , that Ford deemed these blocks not usable for its production car line do to core shift and only bored them to FT bore sizes so to low rpm. I have no real proof of that other than Ford sonic checking 427 stuff to grade it for race, production car application, marine , and industrial.

Nowadays, I try to do minimum bore and spend the money on a piston.  If that really is a thick block after sonic checking, I'd stop at 4.05 and build a snotty 390 or 437 at the biggest.

Ross, what do you do with CJ blocks. Since they have the same cores as the FT?

what is everyone running for valve springs on ford sohc heads.cams will be 282 and .610 lift from racedyne/lsm and jays rockers,new t&d shafts etc.tool steel lw retainers and custom ss intake exh valves.2.350 intake and 2.100 exh valves.
maybe 7k rpm max 489 sohc.in general seat pressure etc.valves are 11/32.

Let's be very clear.  Just because you can get away with something doesn't mean it's optimal. 

Scott, that's why in my response up above, I said to keep your fingers crossed, even after boring.  Back in 2006 I was trying to find a 390 block that would go to a 428 bore.  Sonic tested one.  It tested great in the spots I chose.  Started boring it, then bored a cylinder and ran into a bunch of pin holes where it was thin.  Sonic tested another one, it looked great.  Started boring it, got to a specific cylinder, and found thin spots in it as well. 

You know what would have worked?  4.080" LOL 

A sonic test is a good test, but you can't map every single spot in a cylinder.  There will be spots on the backside where there has been pitting.  You just don't know until you start machining.

Ring seal is paramount especially with modern thinner ring packs.  That's why with aftermarket blocks, such as a Dart/World/Ford Racing SBF block, even at a 4.185" bore size, the wall thicknesses sit at a .250" minimum.  When you're cylinder wall is flexing like a piece of cardboard, you're losing power.

When the FE car engine was introduce, it had a minimum cylinder wall thickness spec of .170 and recommend a max overbore of .060, cutting that down to .140.

I've studied wet sleeve engines and many of them have a .125 wall thickness so, that falls into the area that some (including me) recommend as a min wall thickness when boring a engine. That said, Jay has a dyno mule 427 block, that .060 or a bit under, in places.

The Ford FT block, that came out in '64, is a different matter, they are made with much thicker cores. I don't have the spec but, the CJ block has similar cores. It's my belief that that's where the CJ block was derived.