Anyone drag race with higher gears in the rear end?

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magnumdust

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I'm looking for some ideas. My current setup is a 360, 904, 3000 stall converter and 3.55 gears with 26" street tire(17s/low profile tires). The problem is that the slip on the convertor makes highway driving kind of miserable. Its either revv out to 3000-3200rpm at 65mph or do 50-55 at a slightly less unpleasant 2800rpm. Which is kind of unlivable since i'm use to doing 80-90 in my DD.

So now i'm considering some options to alleviate the problem and gears seem like the best bandaid. Atleast until i can work out some sort of overdrive transmission.

Does anyone use like 3.08s/3.23s and still make good times at the track?
 
No clue yet putting 3.23 S/G in mine soon. I have 5.38's now and does good.
 
Find some 15x8,15x7 ,steel /cop car wheels.Install some used 275/60/15s on em.Usually a 27.5,28.0 tall,swap when you race.Cheapo way out.
 
magnumdust said:
I'm looking for some ideas. My current setup is a 360, 904, 3000 stall converter and 3.55 gears with 26" street tire(17s/low profile tires). The problem is that the slip on the convertor makes highway driving kind of miserable. Its either revv out to 3000-3200rpm at 65mph or do 50-55 at a slightly less unpleasant 2800rpm. Which is kind of unlivable since i'm use to doing 80-90 in my DD.

So now i'm considering some options to alleviate the problem and gears seem like the best bandaid. Atleast until i can work out some sort of overdrive transmission.

Does anyone use like 3.08s/3.23s and still make good times at the track?
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sounds like a garbage converter. what kind do you have in the car? shouldn't slip on the street like your saying it is. going from a 3.55 to a 3.23 the converter slip is going to get worse. sure its converter slip??
 
http://www.bigblockdart.com/forum/speedtire.php

going by the calculator above. it looks like 3000 rpm at 65 mph is pretty dead on with a 26" tire. going to a 3.23 gear will only give ya about 5 mph at 3000 rpm so now you'll be doing 70 mph at 3000 rpm. you can put a 2.94 gear in it and be doing 78mph at 3000 rpm. add an inch to the tires and you'll be around 82 mph at 3000 rpm.

bottom line is without OD everything becomes a compromise.
 
I run a 5:13 gear in my 72 Duster. Rear tires are 29 x 12.5 x 15. It winds quick but the taller tire helped alot. I was running 4:30's previously and that was probobly the way to go. Definately throw a taller tire on your car, fit the biggest one you can in there and test it out.
 
abodyjoe said:
Tests were done on a car with a good converter some years ago and the results showed on that vehicle that 3.55 was the optimum gear for speed vs slippage. There are no cheap options for getting rpm where you indicate you want it (2600?) without tightening the converter and seriously hurting drag strip performance. The best solution that I can think of would be a lockup type converter if anyone makes a unit that would survive what you have for torque. That would require gears, trans, and converter. A power adder of some sort and a tighter converter, with less gear would be a great way to go but expensive. A twinscrew blower makes amazing power and the torque is just like you went up in cubic inches, from about 2200 rpm up. If you set it up for 15 psi boost it will feel and make power like you just doubled the size of the motor. The blower option would require gears a, converter, and a 727 trans as well. If you could get the deal done and tuned for $8,000, that would be cheap for the setup.
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gregsdart said:
Tests were done on a car with a good converter some years ago and the results showed on that vehicle that 3.55 was the optimum gear for speed vs slippage. There is no good option for getting rpm where you indicate you want it (2600?) without tightening the converter and seriously hurting darg strip performance.
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like i said. with a street car everything is a compromise...

modern converter technology has come a long way.. you can get as close to the best of both worlds as possible these days..
 
well crap, scratch that idea i suppose. I guess i better get busy putting together a coil conversion and 5spd setup
 
I have a 300o stall convertor in the Duster. I've had my 4.30's in and ran it on the street. Not out on the highway at 55-60.
But I didn't have any slippage with it.
I change the gears out for long hauls. Got a set of 3.23's for cruising.
I'm also running a set of 255/60-15's on the back most of the time. A set
of 275/50-15 drag radials that I run at the strip.
Never had problems with the convertor. Better get it checked.
 
I ran 235/75/15 truck tires on mine (27.5 tall) and 3.91 gear. then at the track i installed my 26" tall slick. works good. With 4.56's it when on the trailer!
 
I run 275/60/15 4:10 and will be running a new 4200 stall 9 1/2 on the street.
 
Like Joe said it's not the converter that's slipping a lot. That's just how they are with 3.55's and 26" tall tires. I'm running 3.55's in my Cuda with a converter that originally stalled 3k behind the old 360 (stalls 3500+ behind the new 408 but my tires are 27.7" tall so at 65 it's only spinning right at 3000. Not a huge diff. from yours but some due to the taller tires.
 
Nice converter,Fish.Considering the extra 50 to 75 lbs-ft of torque with a 408,you balanced tire size ,gears,converter quite well.
 
Abodybomber said:
Nice converter,Fish.Considering the extra 50 to 75 lbs-ft of torque with a 408,you balanced tire size ,gears,converter quite well.
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Thanks. I didn't know how well it'd work out but didn't have the bucks for a new converter so I tried it and it works just fine. The 408 probably has every bit of 70-75 lbs-ft more torque (smallish but aggressive cam) over the old 360 thus probably the reason for the big change in stall speed.
 
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