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the best gears ?

Started by slim, February 06, 2006, 11:11:56 AM

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slim

so I have a 66dodge charger with a 440-4bbl but its not the original engine and I had it rebuilt (bored out and bigger cam), I'm about positive It has a 727 trans. which I recently had it rebuilt too iI think with a 3500 stall It still has the 8 3/4 rear end. I was wondering what would be the best gear to put in I would really like to be of the line fast ( to smoke all these little rice burners ) but I still want to a high top speed. what should i put in.

694spdRT

You really are not going to get both without an overdrive transmission. My advice would be 3.55's as they give decent off the line performance and are bareable on the highway. Approximately 3000rpm at 60-65 depending on tire size.  You really need to find out what the stall speed of the converter is. If it really is a 3500 stall then any gear ratio that has the engine running less than that at highway speed will create excess heat.
1968 Charger 383 auto
1969 Charger R/T 440 4 speed
1970 Charger 500 440 auto
1972 Challenger 318
1976 W200 Club Cab 4x4 400 auto 
1978 Ramcharger 360 auto
2001 Durango SLT 4.7L (daily driver)
2005 Ram 2500 4x4 Big Horn Cummins Diesel 6 speed
2005 Jeep Grand Cherokee Limited 5.7 Hemi

phat69charger

Slim use this Calculator to test out different gear ratios and transmission combinations to see your RPM's and MPH then make decision based off of your results you get  http://users.erols.com/dmapes/GEARCLC.HTM

phat69charger

I think most members don't realize what to do with or how to use the calculator link I posted to it's full potential, it was shown to me buy an mechanic that's also an SCCA instructor who showed me how he plans out his gearing for the cars that he builds to road race.

The calculator allows you to input your specific information for your vehicle, tire height, final drive gear ratio, transmission gears from a list of six mopar transmissions plus a ford version Richmond 5 speed, or if your transmissin has different gear ratios or you know them you can input them up to 8 gears, I always use the last two gear slots 7 & 8 for comparision of different OD ratios, which is all displayed out for you, in this calculator.

What I did is take someones information from there 2nd Gen Charger like mines that ran a specific 1/4 mile time and that became a reference point for me, I asked them there tire size, rear ratio, transmission type and then I just looked at the speed and Rpm there car plotted out to from the calculator, the only variables that are different between the cars are weight, engine power, operating Rpm and Traction. Take a look my post:  In The Pits - Race Tech about, Traction  http://www.dodgecharger.com/forum/index.php/topic,9630.0.html

Then I just switched final drive gear ratios and trans ratios around to see the different speeds and rpm's, the calculator also shows you the Mph at your shift point if you put in the optional info for a shift point, so most of the time when I see someone ask about what gear ratios should they use or run in there car I think the person asking doesn't take in consideration the variables between cars, an example of what I mean is if two identical Drag cars have the same variables except the Rpm operating range, if one of the engines Rpm limit is only 6500 and the other ones limit is 8500 Rpm the speeds will be different, if you use the calculator you can see the differences between them and you can try to adjust the gearing and try to obtain the same speed from the slower Rpm car.  http://users.erols.com/dmapes/GEARCLC.HTM

If you ask someone about there gearing and you have different variables then they do, you only get a semi close accurate picture of what your  car may do, you should ask them there info about there car then input it into the calculator and see what it plots out to on the calculator, then you have a reference point to compare to your information you input.

Check out these links they are very useful  http://vettenet.org/torquehp.html   http://www.v8914.com/Horsepower-v-torque.htm