Pull a spark plug and insert a dowel rod. Have a friend turn the engine over by hand. Make a mark at the lowest and highest point of the stroke. Measure the recorded stroke. A measurement of about 3 3/4" is a 390, a measurement of 3.5" is a 352/360. The 360 has a 4.05" bore where as the 352 has a 4" bore. No way to know bore for sure without removing the head. Unless you know the truck there is no guarantee what is in there is what it came with, so a vin is almost useless for IDing your motor. I'm guessing you've already easily seen that its an FE by the intake.
Oh and Welcome to FTE!
1976 F250 4x4 Ranger XLT. 445FE, NP435/205, D44/60 4.10
AKA the never ending project.
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