Big block swap for my '66 Barracuda

I knew about the header deal. Fenderwells are what I plan on. I have a nasty stroker 360 motor I originally built for the car but I was deciding more in favor for the RB motor. Actually I have 2 of these cars. A 4 speed and an automatic. Was just thinking a big block 4 speed would the thing for me!! But,,,that 408 motor seems more feesible after all. Appreciate the input.