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Gear Ratios for 1/4 mile small blocks

Posted By: hemiparts

Gear Ratios for 1/4 mile small blocks - 06/25/11 05:18 PM

We are getting the Duster motor back together and ready for the Div2 race in August, what gear ratio are ya'll running in a small block with a 29.5 in tall tire. We have been running a 4.88, but have given some thought to backing it down some to lower the trap rpm. We are using a 5500 stall converter with a stock gear 727 and a .590 lift 312/312 duration cam in a stock stroke 343 cid engine. We apperciate all ya'lls help as always

Chris
Posted By: MIKES_DUSTER

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 05:49 PM

I use 28" tire with 4.56's
Posted By: dennismopar73

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 05:59 PM

430/ 456 either one do fine
Posted By: viperblue72

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 07:20 PM

What is your trap rpm? Seems like you could easily cross the stripe at 7k which I don't see the problem.
Posted By: tubtar

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 07:35 PM

She sounds like a spinner to me.
I guess without knowing where peak power comes in , the best I could do is a bad guess.
I think if you cross at 500 r.p.m. over peak , you are getting the most out of it.
More r.p.m. is just more noise if it ain't pulling.
Posted By: Brian Hafliger

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 07:52 PM

Quote:

We are getting the Duster motor back together and ready for the Div2 race in August, what gear ratio are ya'll running in a small block with a 29.5 in tall tire. We have been running a 4.88, but have given some thought to backing it down some to lower the trap rpm. We are using a 5500 stall converter with a stock gear 727 and a .590 lift 312/312 duration cam in a stock stroke 343 cid engine. We apperciate all ya'lls help as always

Chris



Does the power seem to fall off before 7500rpm?
Posted By: 340B5

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 08:44 PM

I went from 4.56 to 4.88 in my Duster and there wasn't a whole lot of difference except 60' got a little more consistant, and it was easier to miss the 1-2 shift . This is w/2.74 low(904)

Of course the whole combo has to be considered. Mine was 254@.050 ported j's , strip dominator intake.
Posted By: fishy340

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 09:02 PM

5000 stall 440ci sb 3.91 28x10.5 trap 7000g's
Posted By: Leon441

Re: Gear Ratios for 1/4 mile small blocks - 06/25/11 09:20 PM

6.17 let her scream

Leon
Posted By: stevet340

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 01:05 AM

Quote:

6.17 let her scream

Leon



I run 5.86 gears in my 340, spin it up...
Posted By: bdaz smblk

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 02:48 AM

Maybe I should rev my car harder looking at what gears u guy's run.I have a 440 cube with 7,500 conv and 4.86 gear with a 29.5x10.5 tire.
Posted By: dennismopar73

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 02:53 AM

Quote:

Maybe I should rev my car harder looking at what gears u guy's run.I have a 440 cube with 7,500 conv and 4.86 gear with a 29.5x10.5 tire.


Posted By: moparpiff

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 03:45 AM

I run a .02 over 360 with a 4:56, a 4:30 and now currently a 4:10 and they all have been similar. I have only noticed a difference in mph and of course now the 4:10 I am lacking motor for with the 29.5x13.5 tire in high gear. I shift at 6300 and trap right about 6000.

Attached picture 6700240-worldseries.jpg
Posted By: Leon441

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 04:24 AM

Quote:

Maybe I should rev my car harder looking at what gears u guy's run.I have a 440 cube with 7,500 conv and 4.86 gear with a 29.5x10.5 tire.



I ran a 33" tire with that gear at 150. Keep that in mind.

Leon
Posted By: Guitar Jones

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 12:27 PM

I run a 4.86 with a 32" tall tire, shift at 7200 go through the lights about the same. When I had the 340 I used 5.13's with a 29.5 tire, shifted at 8000, whent through the lights about 8000, but I had W5's and a bigger cam.
Posted By: Dartthunder340

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 02:26 PM

Hemiparts, I have been using 4.56's in pretty much the identical combination. I am going to switch to 5.13's this fall.
Posted By: MR_P_BODY

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 03:42 PM

Quote:

We are getting the Duster motor back together and ready for the Div2 race in August, what gear ratio are ya'll running in a small block with a 29.5 in tall tire. We have been running a 4.88, but have given some thought to backing it down some to lower the trap rpm. We are using a 5500 stall converter with a stock gear 727 and a .590 lift 312/312 duration cam in a stock stroke 343 cid engine. We apperciate all ya'lls help as always

Chris



Is that a roller cam and whats the total weight
Posted By: Crizila

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 04:15 PM

IMO 4.56 with that tire diameter would be ideal.
Posted By: hemiparts

Re: Gear Ratios for 1/4 mile small blocks - 06/26/11 11:09 PM

Quote:

Quote:

We are getting the Duster motor back together and ready for the Div2 race in August, what gear ratio are ya'll running in a small block with a 29.5 in tall tire. We have been running a 4.88, but have given some thought to backing it down some to lower the trap rpm. We are using a 5500 stall converter with a stock gear 727 and a .590 lift 312/312 duration cam in a stock stroke 343 cid engine. We apperciate all ya'lls help as always

Chris



Is that a roller cam and whats the total weight




solid lift cam 3210 lbs total including driver.
Posted By: BLONDE BARRACUDA

Re: Gear Ratios for 1/4 mile small blocks - 06/27/11 01:13 AM

depends how you et. I would think 456
Posted By: Evil Spirit

Re: Gear Ratios for 1/4 mile small blocks - 06/27/11 01:05 PM

Quote:

She sounds like a spinner to me.
I guess without knowing where peak power comes in , the best I could do is a bad guess.
I think if you cross at 500 r.p.m. over peak , you are getting the most out of it.
More r.p.m. is just more noise if it ain't pulling.



And a lot of times that "noise" is the rods exiting the block...
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