Good Rear Gear Ratio For Street And Track To Run High 9's Low 10's

[nailheadpowered]

As The Thread Stated Im About To Take My Car To Have The Rearend Done Up With C-clip Eliminators And 31 Or 33 Spline Axles Etc. And While In There I Have A Eaton Posi Unit I Can Put In And Change The Rear Gear Ratio. My Question Finally Is In Order To Get Into My Target Of High 9's What Ratio Are Most Running With The 200r4? Appreciate The Help.

 

[Boost231]

stock. 3.42 is the way to go.

 

[Fuelie600]

stock. 3.42 is the way to go.

Not quite in the 9's yet--but close. I agree with the stock ratio.

 

[gnxtc2]

If you are going to have your diff done, I would scrap the C-Clip eliminators and go with Ford ends. The C-clips will leak over time.

Billy T.
gnxtc2@aol.com

 

[Dabigguy]

Try this calculator. If you have the traction off the line, you want to keep your motor in it's most efficient rpm range as much as possible...even through the lights.

Wallace Racing - Calculate Rear End Gear Ratio needed

 

[nailheadpowered]

thanks for the input the calculator is pretty cool! also on the ford axles how much work is involved for the shop to do that conversion and how is it better than c-clip eliminators? thanks mike.

 

[Dwayne]

I've done the Ford ends. I used 33 spline axles, spool, Ford ends and the Ford rear drum set-up.....couldn't be happier. The Ford drum is alot larger than the factory GM set-up...ie....larger shoes and a larger contact area for the braking surface. Great axle retention with NO leaks, as C-clips are prone to do. I had a total of 1,000$ invested including the labor to have the ends welded on. That price includes axles, brakes, spool, and ends. All parts came from Moser. If you go this route, the rear end must be set in a jig to get the ends alligned straight. Any shop that narrows rears should have such jig...............as for the Ford drum brakes, They were a complete bolt on. Everything was there including pads, backing plates, wheel cylinders, etc.... the only mod I had to make was to bend the original brake line about 20 degrees to go into the Ford brake line adapter......hope this helps.

 

[nailheadpowered]

can i use an eaton unit as i have one that i was looking to put in, and or could i use the stock rear gears also with this but upgrade it for 33 spline, also if you want to can you email me at nailheadpoweredgs@sbcglobal.net the parts and part #'s that you had to get to make this happen. thanks mike.

 

[JayC]

I'd stay stock or maybe even go down a size. I probably shouldn't be posting that tho

 

[Scott Atk]

I use a 29" tire with stock gears. If I had my choice, I would go to a 3.25 - 3.30 gear and use a 28" tire.

 

[SGRIM]

I'd stay stock or maybe even go down a size. I probably shouldn't be posting that tho

Shhhhh:biggrin:

I think the stock ratio would be the best move for you! I would not go down any!

 

[gnxtc2]

Here is a pic of a Ford end with the bearing pressed on the axle:

Billy T.
gnxtc2@aol.com

 

[JC Turbo]

I'd stay stock or maybe even go down a size. I probably shouldn't be posting that tho

I've thought about going to 3.08 gears. Whatcha think?

 

[Dwayne]

Here is a link for the Ford drum brakes... Moser Engineering

 

[bison]

You need to determine your converter efficiency at the traps to get a better handle on the gears needed. From there you can you can go up numerically (3.90's) if your driving through the converter a little bit. Or stay at 3.42 or maybe 3.23's if you are running really efficient. If your slip is under 10% i wouldnt go down numerically. It takes just the right combo to benefit from the gear change. You could restall your converter also. Basically you want to get the engine to hover right in the meat of the powerband for the longest distance possible at full boost and still couple at the top end. This will get you the best et's AND mph. If you go up in gear you will couple sooner, lower numerically you will couple later. You could also run out of gear if you run too high a ratio. This is assuming you already have the tallest possible tire you can get in there. Its possible to go up in gear and not increase the trap rpm much. If you get this effect you know you went in the right direction as the car will run harder in the beginning of the quarter. Please post your trap rpms/mph and the slicks you are running. Believe it or not you could probably benefit from a taller first in the transmission (like the 400's 2.48 1st) and the 3.90's together. It would give you more coupling ability up top and not sacrifice any torque at the axle down low.

 

[onslow]

I've thought about going to 3.08 gears. Whatcha think?

I think: "Long-legged, high speed cruiser." But NO winner at the drags.

I had 3.08s on a '70 Camaro with about 300HP, 350 ft/lbs. I saw 120 on at least two occasions (highway races) and had some juice left.

(Isky cam, Carter 625 AFB, Edelbrock Performer 2101 manifold, K&N 14" open-element filter, Hooker Headers, custom low backpressure exhaust, Global West suspension, Trans-Go 350 shift kit, 15" wheels, Goodyear VR Eagles).

That Camaro wouldn't stand a chance against my TurboB.

Moral: I agree, keep the 3.42.

Steve

 

[TTA850]

I've thought about going to 3.08 gears. Whatcha think?

When I first put my car together I had 3.08's in it, went a best of 10.69 @ 125.8 w/1.47 60ft on 26x11.5x16 ET Streets at 3550lbs. Now I've got 3.42's and 28" tires, quicker and more consistant

 

[JayC]

When I first put my car together I had 3.08's in it, went a best of 10.69 @ 125.8 w/1.47 60ft on 26x11.5x16 ET Streets at 3550lbs. Now I've got 3.42's and 28" tires, quicker and more consistant

I dont know if you've done the math but with the extra 2 inches of tire, there isn't a lot of difference.

I'd like to have seen some runs with 28 inch tires on the 3.08s.

 

[Razor]

My car slowed 4 MPH going from 26 to 28 inch tall tire 3.25 ratio.

4 runs.. within 3 hours.. put the 26 inch tall tires.. same tuneup.. picked up the lost 4 MPH.

Roy's car runs 3.42's on 28 inch tall tires. 8.9's on a stage1, 9.3's TSM weight 109 motor.

 

[TTA850]

I dont know if you've done the math but with the extra 2 inches of tire, there isn't a lot of difference.

I'd like to have seen some runs with 28 inch tires on the 3.08s.

I ran it a few times with 28" tires back then, lost et everywhere just wouldnt run. Snapped an alum driveshaft with that setup. As for not being alot of difference, your right there isnt(about .23 or so)but there is a big difference in traction and consistancy which is what I want.