Small block or big block in a truck?

I bought a 67 barracuda with the plan of putting in a 511 i have. I have since come to the conclusion that a 408 will be a better choice, simply because it fits better in the limited space.
But your pickup has all the room in the world. If it were a daily driver, and mileage mattered, keep the slant, or a mild small block. But if you are looking for a fast, fun ,weekend toy......stroker big block, 100% !