4.10's or 4.56's.........

Discussion of the 5.7L-6.1L-6.4L HEMIs.

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Flannery
Posts: 12
Joined: Mon Jun 27, 2005 8:30 pm
Location: Conway, AR
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4.10's or 4.56's.........

Post by Flannery »

I have a debate I cant figure out.. With my cam that I have I am wanting to go to a lower ratio gear for my truck. The only problem is that I still drive 30 miles to work each day on the freeway ( around 70-85 mph). I was wondering what opinions you guys have for which gearing you would go with. Just an idea of what kind of RPM's I'd be running at 70 or 80 or so.. I just dont want to be buzzing my motor for the 30 miles to work and back each day..

THANKS!!
2003 Ram 2wd RC/SW - 3.92 w/ LSD, CAI, TMR Disabled, Comp. Cams XFI-273 273/277 - .547/.550, BeeHive Springs, Gibson SuperTruck Exhaust, 3"/5" DJM Sus Drop
hemifever
Posts: 99
Joined: Mon Dec 01, 2003 7:04 pm

Post by hemifever »

Since you've got 3.92's now, the 4.10's won't be a difference worth going after. The 4.56's are a nice change. 80mph with 32" tires is about 2500 rpms on my truck. 70mph is 2250 and 60mph is 2000.

How is that cam doing for you? I keep seeing folks having idle and part throttle issues with those comp cams.
1971 Plymouth Cuda - 451 stroker
2003 QC 4x4 Dodge Hemi - STS Turbo, KRC 6005 heads & rods, Ross pistons, 6.1L crank & cam, ARP main/head studs, JBA headers, SMT6, APS converter: 575rwtq/492rwhp @ 9psi
2005 Chrysler 300c
Flannery
Posts: 12
Joined: Mon Jun 27, 2005 8:30 pm
Location: Conway, AR
Contact:

Post by Flannery »

Thanks for the reply, I was leaning for the 4.56's, so your info just made my decision...

The cam does alright unless it goes into the low idle (economy mode I am assuming..idles at 500 rpm instead of the usual 700-800ish are). When it goes to the slow idle it really doesnt like to idle...period, lol. I'm not having that much of an issue with the part throttle, you have to expect that there is going to be a moderate loss in low-end torque from the cam. But from 4500+ its a SCREAMER. I would not recommend towing unless you want to keep the engine wound up pretty good :-? . Over all I am Impressed in the cam profile for the Hemi. And it sounds just as good as it runs!
2003 Ram 2wd RC/SW - 3.92 w/ LSD, CAI, TMR Disabled, Comp. Cams XFI-273 273/277 - .547/.550, BeeHive Springs, Gibson SuperTruck Exhaust, 3"/5" DJM Sus Drop
Flannery
Posts: 12
Joined: Mon Jun 27, 2005 8:30 pm
Location: Conway, AR
Contact:

Post by Flannery »

If you are wondering.. So far I have yet to have a check light come on. Other than the minor idling issues I am having no problems..

I just read about the 6.1 top-end change over to the 5.7.. I wish I read that earlier, it sounds pretty promising since I am wanting to keep it a NA engine, I do plan on running Nitrous but I haven't read yet to see what the low end can handle and the hp shots people are using.
2003 Ram 2wd RC/SW - 3.92 w/ LSD, CAI, TMR Disabled, Comp. Cams XFI-273 273/277 - .547/.550, BeeHive Springs, Gibson SuperTruck Exhaust, 3"/5" DJM Sus Drop
hemifever
Posts: 99
Joined: Mon Dec 01, 2003 7:04 pm

Post by hemifever »

I've seen a LARGE # of folks running the 125 shots. Lot of 75 shots and random 150/175 shots. But ultimately, folks seem to be running the 125's.
1971 Plymouth Cuda - 451 stroker
2003 QC 4x4 Dodge Hemi - STS Turbo, KRC 6005 heads & rods, Ross pistons, 6.1L crank & cam, ARP main/head studs, JBA headers, SMT6, APS converter: 575rwtq/492rwhp @ 9psi
2005 Chrysler 300c
carzrus
Posts: 2
Joined: Wed Jul 21, 2004 12:44 pm
Location: Madisonville, Kentucky

Re:Limited Durango Mileage 4x4 Hemi 3:55

Post by carzrus »

After 36,000 miles our Durango is now getting between 18-19.6 on the highway and 16teenish mixed, we have the 3:55 rear and this helps with the mileage gain.
:wink:
hemic03
Posts: 6
Joined: Tue Jan 17, 2006 3:17 pm

Post by hemic03 »

get a 2500 stall torque converter and keep your 3.92 gears, it might not be as quick 0-60 as 4.56's but I am pretty sure you will be better gas mileage, and a couple tenths off your 1/4miles time with a torque converter. With your cam now and the 3.92 gears, the torque converter would get all those components working great with optimum performance.
Aps makes a great torque converter
03 Dodge Ram Hemi Rcsb
3.55 LSD

Mods- 6.1 Cam with manley perforamnce parts, dynatech headers, motoblue underdrive pulley, Afe Cai, Gibson Super Truck exhaust, Superchips, electric exhaust cutout after cat.
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