Very much a debate for me of which way to go. I want thick cylinder walls, not barely. also if both are made efficient does anyone know how much gas mileage is effected, I am leaning towards a 460 with AFR heads, with the cam I got planned it would have lots of power and smooth idle. Does anyone have any info how much cubic inch effects gas usage. I say this because the production LT1 motor gets as good or close as the coyote motor yet cubic inch is different. 307 vs. 376. Then we have other issues like bore and stroke, piston speed and how this all affects efficiency. I also believe that a good quench although may not effect WOT power as much as some have found , still has a lot to do with efficiency of a motor especially at part throttle as well as a big help towards pre ignition resistance. There are many things to consider besides peak power at WOT. Some here have experience, would love to hear from.