A prototype 3D MRF sequence was evaluated for cortical T1 mapping at 7T in the context of the Human Connectome Project (HCP). Phantom results showed that the 3D MRF T1 map of a liquid was in good agreement with gold standard IR-SE measurements. The synthetic MPRAGE and synthetic T2-SPACE created from the 3D MRF data performed well in HCP pipeline. The cortical thickness estimation was fairly stable across different imaging resolutions. The R1 of the cortex showed higher value than expected, which may indicate that more advanced signal models may be necessary to accurately describe the spin dynamics in-vivo.