What is your timing set at? Take a look at your plugs. If it is running lean they will have a whitish tint. If it's rich they will be sootie black. I would start there, it's important to see what the plugs look like so that we can if it's lean or rich.
It does look like you have a sufficient cooling set-up but has it always ran a little hot or did it strat when you put the motor in? Also, what size thermostat do you have in?
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SVO siamesed 351 stroked to 417ci,Yates heads, solid roller,Trans King glide and a little blue bottle
of giggle gas.
My Car