Check around aftermarket springs, Manley & Comp's are high and that is what KRC uses. I know for example if you have the 4.7, you can get the Mopar H.O. springs that are plenty beefy (the 4.7 H.O. enging, which I have in my Grand Cherokee Overland, has an upgraded cam that requires thebeefier springs) and many people who upgrade their springs in the Hemi replace the rather weak 5.7 springs with the 6.1 springs, again plenty strong enough for all but the crazy high loped cams. These two Mopare offerings I believe are under $10 each right from the stealership...

The HP gains can be moderate, like 35 or so from a mild grind which needs no other mods to work and can get crazy with the aggressive grinds that require major headwork just to clear them. 420 rear wheel (which equates to about 550 HP at the engine) is attainable in a naturally asperated Hemi, with headwork, custome tune, springs, retainers, damper, cam tunerand a few other mods to accomodate it...

 

The cams suggested above will DECREASE torque
in all but the highest rpm range.

Switching to an electric fan
compared to the viscus clutch fan
won't improve engine shaft torque
during the time the viscus clutch is unlocked
...which is anytime the coolant is below 220 degrees F.....
because you will be running the electric fan when the coolant is that high anyway
and the amps it will draw will load down the alternator and steal torque from the engine shaft.

On the 2009 5.7 Hemi with variable valve timing + 1.2 more CR
Dodge was able to up the torque at 4000 rpm from about 375 to 400ish.
That is about a 6% improvement
and would be what a 3.7 V6 owner would expect
if a low to mid range rpm camshaft grind was installed.

If you try to build a 3.7 v6 in a heavy pickup into a high rpm 'screamer'
it won't be a good 'daily driver'
or a better 'off roader'

 

I have been looking at doing the E-Fan for a long time but know one has been very straight forward about the install. I have no idea how to do it basically and even a written write up would be nice. Or some pointers.

 

A quick google search showed a bunch, here is one with LOTS of pretty pictures...

http://good-times.webshots.com/album/562290284LMqGCv

 

Once again, your knowledge just overwhelms me.[&:]

[align=left]XFI™ 5.7L & 6.1L HEMI CAMSHAFTS[/align][align=left]The new COMP Cams® XFI™ (Xtreme Fuel Injection) camshafts for Hemi-powered Chrysler vehicles[/align][align=left]dramatically increase engine horsepower and torque, yet retain compatibility with reprogrammed OEM[/align][align=left]vehicle computer systems. Available in three different profiles (XFI™ 260, 268 and 273), the new camshafts[/align][align=left]are uniquely engineered for street performance and towing applications.[/align][align=left]In recent dyno tests performed on a Chrysler Hemi engine (outfitted with COMP’s #26918[/align][align=left]Beehive™ valve springs and upgraded exhaust), the XFI™ 260 camshaft netted 20 additional[/align][align=left]ft lbs of peak torque in lower rpm ranges and 31 additional hp. [/align][align=left][/align][align=left][/align][align=left][/align][align=left][/align]