The GT 5.4L was a specialized Ford Modular engine. Ford Modular Vs don't imply specific parts sharing, but rather that all modular V8 and V10 engines can be produced in the same factories with the same tooling as any other modular engine within hours.
IIRC, all 5.4s (Including Shelby and GT motors) had the same bore (90.2mm) as the old 4.6L Mod V8s in old mustangs and shared other bits like firing order (1-3-7-2-6-5-4-8).
Here's a breakdown:
4.6L 90.2mm bore, 90mm stroke, 227mm deck height, 100mm cylinder spacing.
5.4L 90.2mm bore, 105.8mm stroke, 256mm deck height, 100mm cylinder spacing
5.0L Race engine 94mm bore, 92mm stroke, 227mm deck height, 100mm cylinder spacing
5.0L Mustang engine 92.2mm bore, 92.7mm stroke, 227mm deck height, 100mm cylinder spacing, new firing order but I don't remember it, haven't worked for ford since 2008.
6.8L V10 90.2mm bore, 105.8mm stroke, 256mm deck height, 100mm cylinder spacing, Firing order (1-6-5-10-2-7-3-8-4-9)