Since i bought my '05 Ram Quad Cab 4.7L in April of this year, i have made several modifications. Such as a dual Rhino exhaust, air raid cold air intake with an AFE air filter(dont ask i had to mismatch becaue its a 4.7L), Jet power chip and a throttle body spacer. Also i just had 33inch mickey thompson's put on my truck. From the factor the 4.7L has 235 hp and i have added around 100 hp and i am always looking for ways to add more horsepower. Any ideas? The question that i have is about the rear end gear of my truck, i noticed after i added the larger tires that the exceleration has declined a little bit. So, do i need a different gear and if so what gear would be right for my truck?
Thanks,
TEX  

You need the 4.56 gears, period. It will improve your accelaration and gas mileage. I'm going to take a guess here and say you probably have the 3.92 gear, correct? If you go up a little to the 4.10, you'll see a little bit of performance gain, but not enough to justify the cost. But doing a 4.56, it will gives you many options later on.  

No offense, but I would have gone with the Hemi to start with. With those, you're STARTING with 345 horsepower. But I hear where you're coming from. Have you had it dynoed? You sure it's 100 more HP? I'd be really surprised if just a chip, filter & throttle body spacer would give you that much more power. I'd maybe look at cams & headers if you really want to wake it up. Naturally, a blower will give you more power than just about anything else.  

First off, you DID NOT add 100 hp. You are lucky if you added 30 hp. A cold air intake on the 4.7 adds approximately 6-7 hp, the jet chip (which is junk in my opinion) added maybe 10. Your exhaust added maybe another 10. The throttle body may have added 1 or 2. The filter really didn't change much, you might have gained 1 hp. The 4.7 is in no way a dog engine, but your modifications will not get you the horsepower difference they would if you applied the same mods to a hemi. Here is some advise to free up some power on your truck: 1)Change to full synthetic fluids - everything - engine oil, trans, rear axle, power steering. 2)Install an electric fan. the belt driven fan is robbing you of at least 10hp. 3)Install a cooler temperature thermostat - cooler engine, more power 4)Install better plugs/wires. Champions are junk, buy NGK plugs! They are the best in the Dodge engines. 5)Change your cats to hi-flow cats, and install some headers. These 5 things, combined with your other things you mentioned, should get you closer to your 100hp. As for the gearing, it doesn't gain you hp. It does change your take off launch, and acceleration speed. Depending on what gears you already have will depend on how much difference it makes. 4:56 gears are the best in the Ram for what you are wanting to accomplish. Check with 3rdStrikePerformance.com. They can hook you up.    

Yeah, gearing is a trade-off. If you get super-short gears, your truck will hustle around town, but will eat gas like a bad habit on the freeway. The only time I'd really re-gear is if you did a dramatic change in tire size over stock.  

not to send everyone to one website but this guy knows hes stuff.. yes u need 4.56 cause the 33 is just a big tire.. + u gonna need a recalibration of the speedo and odometer..


goto www.airram.com
he has ported n polished heads and cams for the 4.7l  

4.56 still seems a little short for 33s, but it'll probably go like a bat out of hell. Thanks for the heads-up about the guy that specializes in the 4.7.  

I've got a 4.7 in the Demon. If I add up HP what each mod I installed says they add, I'm pushing 500 hp.     LOL! Yes, I know better and I'm not making fun at anyone. Just look at what each little things says that adds HP and add it up. It's funny. The biggest thing that I've heard that adds HP is cams and a 70mm TB. Sure, adding things like headers, exhaust, computer reprogrammed and gears can turn a 4.7 loose. HP cost $$$ and it's all in how fast you want to go. Me, I'm a cruiser, but every now and then I do put my foot into it.