keeping horespower and torque with lift and tires

[Johnbales]

I have a 1997 Silverado 350 vortec installing a rebuilt 4l60e this weekend, I have a dick cepek 6.5 stage one lift kit I got with a parts truck, and I'm buying 35s on twentys with graduation money. What's a way to keeping the original horsepower when lifting it? Like is gearing it do a lot or is it not worth it? And if it is how much does that cost ?

 

[great white]

Gearing.

You need lower gearing since your larger rolling diameter raises the over all final numbers (for example: 3.73 to 4.10). Lower gears keeps you at overall ratio you are right now.

There are also weight and leverage penalties with larger rolling stock. You can go a little lower than what is required to keep your current ratio which will compensate for your larger mass, but you will be running a little higher RPM everywhere.

You will also need to change gearing to correct your speedometer output. Larger tires throws off you r speedometer/odometer. If you are obd II, larger tires will effect torque converter lockup and possibly shifting.

If you go lower than what is required to bring your overall ratio back to stock, you will have to correct the speedometer output. If you're OBDI, you do it with jumpers int he DRAC/VSSB. If you're OBDII, you do it in the PCM calibration.

 

[Johnbales]

Thank you that's what I thought, but not in detail of what it does, do you know what that would run in price?

 

[great white]

That's what I thought, would you or anyone else know what that would cost and what gear ratio would be best?

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Depends on what your rear ratio is now, the final height of your tires and the weight. There's lots of simple gearing calculators on the web if you google for them.

Cost for parts and labor varies depending on where you live. I'm thinking Alaska is going to be more expensive than most....

 

[Jizanthapus]

If you don't do the install yourself for gearing, you're looking at $350+ just for install of the gears. The gears themselves are around $180. Then depending how you recalibrate your speedo, that's $. I did the gear change in the final drive of the transmission. $15 part, $50 installed.

Just for your reference, I did a Eaton Posi diff ($445 @jegs), 4.56 gears ($180)[6" lift on 35's], diff install kit ($110), new axle bearings and seals. In the end it was $1,300 out in California.

 

[oohunter04oo]

If your going to run 35's then 4.56 gears will get you back close to stock. I spent $1300 on gears front and rear, 2 installation kits and locker for the rear. I installed them myself, but most shops around here quote $500 per axle to install gears.

 

[98_k1500]

Do some research on stall converters. My 2500 is a touch high for driving in town every day. I would suggest a 2000 or so stall. They can be had for around $150, and will increase your takeoff power substantially. Be sure to get a lockup converter so your highway mpg wont suffer. This is the best route to keep your speedo decently calibrated and regain some of your lost power. If you rebuild your trans, the corvette servo kit is well worth the money. It really brings 2nd gear to life.