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#2401351 - 11/10/17 09:40 AM 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
grancuda Offline
super stock

Registered: 04/28/06
Posts: 706
Loc: Central US
This winter I am thinking about setting up different rear axle gears for my '67 383 Barracuda w/ a 727 & 4.10 SG. I am not sure how taller gears vs shorter slicks at the track would perform.

Here's how it's set-up
68 383 B motor w/10:1 compression
Edelbrock E-Street heads
Cam - Comp XE274H
230/236 @ 0.50 duration
LS of 110*
Intake CL 106*
.510 lift @ intake valve
.523 lift @ exhaust valve
Holley 850DP
Edelbrock performer RPM
Stock style converter (1800 rpm)
8.00/8.50-14 (27.5") M&H Racemasters
Weighs 3,090#

My best with this set-up is
R/T - .059
60' - 1.969
330' - 5.442
1/8 - 8.303
MPH - 85.52
1000' - 10.787
1/4 - 12.883 @ 107.81 mph

So with all that said, I have been told I could go faster with a 3.73 gear. I always thought the 4.10 would get it going quicker out of the hole. I always thought you set it up to go redline @ the end of the 1/4.

As it is, I'm @ 5,500rpm at the stripe.

I have thought about maybe a 3.55 or 3.73 & a 26.0" slick. Then I could run 28.0 tires still on the street & reduce highway RPM. That change on the track with a 26" tire (3.55/3.73) puts me at 5100/5350rpm at the stripe.

I am considering a better converter, maybe a Dynamic Converter, to get it off the line & get my 60' down. I just want it to be a fairly tight because it's my daily driver.


_________________________
1967 Barracuda Formula S 383
1969 Dart Custom 2dr HT 440
1972 D1oo SWB 360
1980 Macho Power Wagon LWB 318
2010 Ford Raptor 6.2L
2014 Challenger R/T Shaker #0488

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#2401363 - 11/10/17 10:04 AM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
A/MP Online   content
mopar

Registered: 10/09/08
Posts: 512
Loc: East Coast
Faster, a little, but quicker no. You're probably making 350-375 HP. If it hooks and goes then maybe a 26" tire might hook, but I'd say no. You want the largest contact patch that you can stuff under the wheel well. 9X29X15 will give you the best grip for a standard wheel well using a 10" wheel. Run a taller street tire to keep the R's down,cheaper than a gear swap. 3000-3500 stall converter built to your cars specs. That should get you to 12.5's . Look up Richmond gear calculator and plug in the numbers. This is only a guide

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#2401380 - 11/10/17 10:46 AM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
fast68plymouth Online   content
I Live Here

Registered: 01/20/03
Posts: 10333
Loc: So. Burlington, Vt.
I'm sure you could do something like 3.73's and a T/A "tight" 10" converter, or a Dynamic tight 9.5" and not lose any ET.
_________________________
68 Plymouth Satellite, 383, stock 906's, 3550lbs, 11.18 @ 123, 1.51 60' PRH is a Comp Cams W/D......competitive pricing on entire line. Custom cams available. ** dealer for Indy Cylinder Heads **

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#2401402 - 11/10/17 11:45 AM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
rb446 Offline
member

Registered: 10/17/15
Posts: 183
Loc: UK
I would go 9x28's>9's keep the 4.10's and get a purpose made converter that flashes to at least 3000 for a 383, that 1800 verter is killing your 60/ET. Your mph/weight shows you are using around 307hp of whatever hp that motor is making which should be 350+?, its just not being allowed to unleashed itself early enough...you got a low 12 potential car there.






Edited by rb446 (11/10/17 11:46 AM)
_________________________
1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987

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#2401421 - 11/10/17 12:27 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
Tommy D Offline
enthusiast

Registered: 10/02/08
Posts: 355
Loc: Harleysville, PA USA
Here's a handy formula that will tell you all you want to know.

(MPH in 1/4) x 17.6 (constant)/ (Tire diameter x 3.14 (Pi) x 60 (constant) x gear ratio.

Your current combo would look like this:

107.8 x 17.6 / 28 x 3.14 x 60 x 4.10 = 5308 RPM


I did this for an old combo on my RR and it helped.

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#2401424 - 11/10/17 12:38 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
crackedback Offline


Registered: 02/15/15
Posts: 902
Loc: CA
Want it to go faster, work on the 60' as it's REALLY soft. You've got a 12.00-12.20 MPH in a 14.00 chassis... 14.00 cars go 1.95 60's. You should be in the very low 1.7x range or even high 1.6x for that MPH if the chassis is good.

Gears won't do much when the chassis and converter aren't helping you at all.

I'd spend money on a good converter that flashes at least 3500. That will wake it up a bunch! New converters aren't the marshmellows of the old days either.

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#2401454 - 11/10/17 01:41 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: crackedback]
gregsdart Offline
master

Registered: 01/21/03
Posts: 8092
Loc: Frostbitefalls (Rocky&Bullwink...
Originally Posted By crackedback
Want it to go faster, work on the 60' as it's REALLY soft. You've got a 12.00-12.20 MPH in a 14.00 chassis... 14.00 cars go 1.95 60's. You should be in the very low 1.7x range or even high 1.6x for that MPH if the chassis is good.

Gears won't do much when the chassis and converter aren't helping you at all.

I'd spend money on a good converter that flashes at least 3500. That will wake it up a bunch! New converters aren't the marshmellows of the old days either.

I agree. Spend the money on a good converter, as that will get you the biggest gains. Call a good converter builder and ask them what they recommend for their converter, and what gear would so suit you best.
_________________________
GREG
Educated at SHK U
Measure with yardstick
mark with chalk
cut with torch!



528 cubic inch alky injected 440-1 wedge, 3055 race weight.
8.779 at 153.16 mph. 1.289 60 ft. density altitude 1617 feet. Best 60 ft 1.24

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#2401461 - 11/10/17 01:53 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
rb446 Offline
member

Registered: 10/17/15
Posts: 183
Loc: UK
Just did a quick calc, if we assume you have 350hp at the crank and keeping those slicks/gears you have now, with the right converter this is possible if it still hooks with the added hit>

60 Foot E.T. : 1.67
1/8 Mile E.T. : 7.60
1/8 Mile Trap Speed : 89.48
1/4 Mile E.T. : 12.04
1/4 Mile Trap Speed : 111
1/4 Mile Trap RPM : 5,580+slip or 5300+ w/9x29" tyres


Edited by rb446 (11/10/17 01:53 PM)
_________________________
1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987

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#2401462 - 11/10/17 01:55 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
Bad340fish Online   content
master

Registered: 01/20/03
Posts: 5336
Loc: Tulsa OK
From what I have seen the better the converter the less the rear gear even matters. With the stock converter a change to a lower gear usually shows big gains. When a good converter is in place before the lower gears those gains are usually much smaller. My car picked up .7 going from a 3.23 to a 3.91 when it had the stock converter. A friend of mine with a similar combo did the converter first before the gears, his car picked up zero ET going from a 3.23 to a 3.91 because the converter was doing all the work.
_________________________
68 Barracuda Formula S 340

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#2401478 - 11/10/17 02:21 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
rb446 Offline
member

Registered: 10/17/15
Posts: 183
Loc: UK
I ran my 340 Cuda with 3.55's 8x26" slicks, a B&M s/holeshot verter and went 13.31@101. I added a better cam/carb/intake, 4.30's, T/A 4200 verter, 10x28's and went 12.39@108.5, weight stayed the same at around 3550. Using weight/mph shows I added approx 50hp to the motor and thats not a 1 sec gain in ET.


Edited by rb446 (11/10/17 02:31 PM)
_________________________
1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987

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#2401485 - 11/10/17 02:33 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: rb446]
GY3 Offline


Registered: 12/13/13
Posts: 2095
Loc: Wichita
Optimal 1.72 60 ft. Would yield a ~12.38 according to the wallace calculator using your mph.
_________________________
'63 Dodge 330
11.19 @ 121 mph
Pump gas, through the mufflers on street tires with 3.54's


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#2401534 - 11/10/17 04:38 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
mopar dave Offline
master

Registered: 01/04/07
Posts: 5236
Loc: flint michigan
I switched to a 4.30 from 4.10 when i had a 408 and seen nothing on my slip. I did have a 8" Lupo convertor as well. I did pick up rpm at the strip thou which was something. Went from 6800 to 7100. Now need to put the 4.10 back in for the 511.

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#2401594 - 11/10/17 06:47 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
BSB67 Offline
master

Registered: 02/19/05
Posts: 3368
Loc: Prospect, PA
I agree with those that say look to The converter if you are trying to be quicker in any meaningful way. The 1.7 and 12.4 would be realistic.
_________________________
500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes 4150 lbs with driver, 3.23 gear, stock converter 11.68 @ 120.2 mph

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#2401724 - 11/10/17 10:43 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
Dave Hall Offline
super stock

Registered: 01/21/08
Posts: 1192
Loc: Cotati, CA
I was kinda thinking the gear should go the other way but a great converter can make up a lot. If it were me, I would use a 4.56 and shift it at your 5,300 and hope it goes 6,500 through the lights. It probably won't though. Most Stockers are in high gear before the 660 but 4.88's and 5.14's probably are a bit much for most guys. It's expensive to really optimize 60' times. Guys have 4-5K of converters laying around. Center sections are not cheap either.

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#2402497 - 11/12/17 11:10 AM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: crackedback]
383man Offline
Too Many Posts

Registered: 01/19/03
Posts: 26459
Loc: Balt. Md
Originally Posted By crackedback
Want it to go faster, work on the 60' as it's REALLY soft. You've got a 12.00-12.20 MPH in a 14.00 chassis... 14.00 cars go 1.95 60's. You should be in the very low 1.7x range or even high 1.6x for that MPH if the chassis is good.

Gears won't do much when the chassis and converter aren't helping you at all.

I'd spend money on a good converter that flashes at least 3500. That will wake it up a bunch! New converters aren't the marshmellows of the old days either.



Thats what I would do is get a good converter for the combo and work on the 60. The gear in it now should work fine.
My old 383 Dart years ago was a 452 iron headed 383 with the MP .484 cam and stock 9.5 comp. I ran a tight 3000 Turbo Action converter in it with 26" tires and 3.91's. It would 60 in the 1.70's with about a 1.76 being normal. And it ran a best of 12.31 @ 110. Get a good converter built for the combo and get that 60 down. Good luck , Ron
_________________________
My car...63 Sport Fury Max Wedge wanna be street car..with new 493 pump gas full exh eng.......10.76 @ 124.49 ! ! ! My page on the cool 62-65 Mopar site ! http://www.1962to1965mopar.ornocar.com/mmo82008.html

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#2402552 - 11/12/17 12:15 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
Cab_Burge Offline
Too Many Posts

Registered: 08/23/03
Posts: 29562
Loc: Bend,OR USA
383 motors need to rev to go fast at the 1/4 mile tracks shruggy Short stroke motors need all the help you can give them up
That being said what RPM are you shifting at now?
Did you degree the cam? If so is it straight up, advanced or retarded?
If I was you I would work on the 60 ft. times, carb. squirters and traction first up Is it spinning or dead hooking?
What size squirters are in the carb now and are you still using the 50 CC rear pump? If you have # 35 or bigger squirters try some # 33 or smaller and if your still running the 50 CC pump swapping it out to a 30 CC pump. twocents
_________________________
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)

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#2402643 - 11/12/17 03:36 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: grancuda]
fast68plymouth Online   content
I Live Here

Registered: 01/20/03
Posts: 10333
Loc: So. Burlington, Vt.
It's got a fast rate hyd cam in the motor....... So it's not going to rev real high, whether there is potential hp up there or not.

The OP wants to take gear out of it to make it more street friendly, but doesn't want to kill the ET.

With those variables in place, there aren't a lot of options.

The motor should easily make 400hp, if the valvetrain will stay happy high enough in the powerband to let it.
The RPM heads would certainly provide enough flow to facilitate a hp peak of over 6000rpm, but I'm not too confident the lifters will allow that to happen.

This is one of those situations where the intended use of the car, and the overall combo in general would make it difficult for the engine hp and the on track performance to coincide very closely.
_________________________
68 Plymouth Satellite, 383, stock 906's, 3550lbs, 11.18 @ 123, 1.51 60' PRH is a Comp Cams W/D......competitive pricing on entire line. Custom cams available. ** dealer for Indy Cylinder Heads **

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#2402686 - 11/12/17 05:05 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: fast68plymouth]
rb446 Offline
member

Registered: 10/17/15
Posts: 183
Loc: UK
Originally Posted By fast68plymouth
It's got a fast rate hyd cam in the motor....... So it's not going to rev real high, whether there is potential hp up there or not.

The OP wants to take gear out of it to make it more street friendly, but doesn't want to kill the ET.

With those variables in place, there aren't a lot of options.

The motor should easily make 400hp, if the valvetrain will stay happy high enough in the powerband to let it.
The RPM heads would certainly provide enough flow to facilitate a hp peak of over 6000rpm, but I'm not too confident the lifters will allow that to happen.

This is one of those situations where the intended use of the car, and the overall combo in general would make it difficult for the engine hp and the on track performance to coincide very closely.[/b]


EXACTLY......at 400hp? that car has 11.5 potential then, I don't think that is going to happen from 12.8's though with just a converter change.


Edited by rb446 (11/12/17 05:11 PM)
_________________________
1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987

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#2402845 - 11/12/17 09:51 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: rb446]
sixpackgut Offline
Drag Week Mod Champion

Registered: 06/08/03
Posts: 8961
Loc: Charleston
A friend asked me to tune his carb on a chassis dyno on sat. I picked up 113 hp. 50 hp in it wasnt going full throttle 63hp in the carb tune. Just pointing out that sometimes there is more in it

I would put in a 3500-4000 9.5 converter with 3.73s if it was me
_________________________
Gen 3 power 6.22@110, 9.85@135

performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs

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#2402853 - 11/12/17 10:08 PM Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times [Re: fast68plymouth]
BSB67 Offline
master

Registered: 02/19/05
Posts: 3368
Loc: Prospect, PA
Originally Posted By fast68plymouth
........if the valvetrain will stay happy high enough in the powerband to let it.
The RPM heads would certainly provide enough flow to facilitate a hp peak of over 6000rpm, but I'm not too confident the lifters


Considering his question, I wasn't going to go there.

Can't remember my Comp Cam part numbers, but I bet their 282 solid (xs282?) would put some power/mph in it, not to mention rev to the moon. Seems like smaller engines with short strokes that like to rev a fast rate cam is like a double wammy.
_________________________
500" NA, Eddy head, pump gas, exhaust manifold with 2 1/2 exhaust with tailpipes 4150 lbs with driver, 3.23 gear, stock converter 11.68 @ 120.2 mph

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