The curves are out there. They have have broad torque curves and start low.
Don't confuse lag with boost threshold. Very few turbo engines make boost off idle.

You can make a V8 have a similar torque curve. Here is a graph I made comparing my old turbo setup to an Ecoboost. (I added 18% to my rear wheel dyno numbers to give me a rough idea of crank numbers).

 

Welcome to the "one V8 engine fits all" world. The Hemi was designed to be used over a broad spectrum of vehicles - trucks, SUVs and cars. As such, it does really lack the true low end "grunt" that engines designed solely for use in trucks possess. The 5.7 Hemi can be made to be a low end beast, but it takes some modding. Numerically higher gears is a good place to start plus there are a few cam grinds out there that will make you feel like your driving a CTD if you didn't know better...

 

I have a co-worker who just bought an eco-boost. And he just bought a tuner for it. Says its night and day difference. I've heard the gains with a tuner are somethin like 50 horse and 100 more torque at the wheels!

 

Don't forget it's not just boost that gives them such a great torque curve but also the variable valve timing plays a large part in that as well.

 

Numerically lower gears wont do anything to the motors torque curve.
Its definitely all in the cam and intake runners.

 

I don't recall seeing Hammer say they did. Maybe you read it differently.

 

That is correct, re-gearing wont change a thing at the crank, however they get the RPMs up into the powerband sooner and then help to keep it there. So the perception is higher torque and more HP. Plus since the RPMs stay in the powerband there is much less tranny searching.

Plus let's not forget the effective gear ratio when running larger tires. A stock Ram even with 3.92 gears at 31.5" of tire has an effective ratio down around 3.6 when running even 33" tires. I've driven a 4th Gen with it's 390 HP Hemi, QC 4x2 with 3.21 gears from the factory and 33" tires on 20" wheels. The thing was sad to me and running on the interstate at all of 1400 rpm when you give it gas to pass someone the lag is pathetic. Feels like there's a 110 HP 4 cylinder in the thing until you get the RPMs up enough for power to build.

GEARING MAKES A HUGE DIFFERENCE, even if it doesn't directly effect engine performance...

 

Absolutely! I had a 97 Cobra with a high revving 4v motor (7000RPM redline). Going from 3.23s to 4.10s was AMAZING.
These hemis would do better with a better cam grind and longer intake runners (think the old TPI chevy motors).

 

This is off subject but Id much rather have a cam grind then a new cam.
Where do i start. Pm me if you have to

 

And there it is folks... How long and how many miles would it take to recoup that 10 grand in slightly improved fuel economy??? YEARS. And YEARS. the way things are now, you're far better off driving what you have and paying it off, than you are to chase the holy grail of better fuel economy. Talk about saving money... What if you banked that money you used to spend on a truck payment! Suddenly 4 dollar gas wouldn't be such a pain in the wallet.

It always amazes me how people justify bumping up a monthly payment by a couple hundred dollars to save fifty in gas... It's like preferring to pay a mortgage company 20K a year to keep from paying uncle Sam 4K in taxes instead. I'm all for owning a house, but get it paid off and LIVE!