Zoomies=not street legal. So what exactly are you doing with the Bronco? Sounds like a mundane question, but are we drag racing, mud pits, hill climbing etc etc.
Something that need High HP, stick with the "small" block and stroke the shyt out of her. Something that needs ballz-to-the-wall torque, ya just can't beat a big block.
I for one, am a HUGE fan of the sound a small block Ford makes at 9,000 RPM!!! Makes my tongue hard in fact!
In a nutshell, whatcha doin with this beast?