newly built 416 getting warm

thanks for all the feedback. some good points on the break in and timing. the timing does need to be kicked back. im getting some detonation under load up hill and when getting hot so thats the first step. i waited to see if a full mixture of 93 octane would do the trick but its not. if the break in and timing dont solve it i will probably re-core the original to a 3 core and go with that. its a new o.e.m. radiator so i dont want to waste it. hopefully that will be enough. thanks again.