347cid making 500ft#? Yeah, in a
NASCAR engine. All you have to have is $60,000 and you can slap a 500ft# 358 in your sleeper.
An 8.1 GM has 150 more cubes and a lot better volumetric efficiency, computer controlled combustion and makes only 450ft# (that's installed, not bare engine on a dyno). I'm all for toking on the crack pipe, but be real. Torque is all about volumetric efficiency. It's about how much air and fuel a cylinder can injest in a single cycle. If you aren't running a motor 7,000rpm then you aren't seeing the ram effects that let an engine over-perform its displacement. For us people that take off from an idle, we'll be lucky to see one ft# per cubic inch. You need an engine you use at 9,500rpm to make 500ft# from it. That air in the intake runners has to be moving super fast when the intake opens to hammer in enough air to burn the fuel for 500ft# on a small motor.
Or you need a turbocharger. A diesel that size has no problem making the 500ft# because it has the turbocharger.
For street engines, you NEED displacement to make big torque where we drive. A 350ish motor can make 500hp with the 350ft# a GREAT set of heads (not cast iron factory shit) will give it--but it has to spin. And 3.50 gears would be pathetic because they don't let it spin.
There's a big difference between a race engine--which would be useless on the street because there is no opportunity to get it into the revs it needs to be in, and a street engine which has to operate from idle-6,000. A 358" NASCAR engine would not be impressive in that truck because to get it going it would idle at 2,000rpm because the low rpm characteristics are so horrible it won't run below that. These engines last 600 miles and never see less that 7,000rpm during operation.