Depending on how much work you want to do here is what I did. I removed the heater core, plugged the outlet on the timing cover fo the heater hose, and routed the water from the back of BOTH heads using the 301 nipples mack to the water crossover. Many have done this with excellent cooling results. Below is a pic of my setup before I put my intake on.
Honest dad, that 455 on the side of the block is a serial number
