Hey y'all, made an account just for this, wanted to see if anyone had a similar encounter.
My dad purchased a 2012 Lariat brand new (12/11 build date), and it was passed on to me about 3 years ago, in typical 18 year old activities i decided to start modifying the engine, shorty headers, intake and manifold, tune, the basics. The engine started having a weird ticking, maybe lifters or worst case rod bearings, I accidentally brought 'er over 7k a handful of times, so I decided theres no better time to redo the engine than the present, and maybe put some power into it. I got head studs, MMR timing kit, an upgraded oil pump, valve springs, cams, and brought it to my main performance guy, he just got the engine torn down and while going over the studs we found that they dont fit, ARP 2564702 for the 2011-2012 mustang/f150 doesnt fit my 2012 f150? We thought it mightve just been a parts mistake, but every search came up with the same kit, and after looking at the block, it was stamped 12/16/12 around the water pump, making this block a 2013. After looking through service records for the truck, there is no record of a new engine being swapped in, nor any repair/short block being installed. Asking my dad came up with the same conclusion, and it makes me wonder if this has ever been seen before?

 

Maybe. Search for oblong cylinder problems with the 5.0 if you like going down rabbit holes. They did do a block update around that time. I wouldn't have thought it would impact studs, though. That doesn't make sense. And I would have thought the Mustang and F150 versions would be the same for studs, also.