4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
#2401351
11/10/17 12:40 PM
11/10/17 12:40 PM
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Joined: Apr 2006
Posts: 1,012 Central US
grancuda
OP
super stock
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OP
super stock
Joined: Apr 2006
Posts: 1,012
Central US
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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 1967 Chevy C10 Short Stepper 1980 Macho Power Wagon LWB 318 2021 Toyota Supra
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2401380
11/10/17 01:46 PM
11/10/17 01:46 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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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 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2401402
11/10/17 02:45 PM
11/10/17 02:45 PM
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Joined: Oct 2015
Posts: 570 UK
rb446
mopar
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mopar
Joined: Oct 2015
Posts: 570
UK
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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.
Last edited by rb446; 11/10/17 02:46 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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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: crackedback]
#2401454
11/10/17 04:41 PM
11/10/17 04:41 PM
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Joined: Jan 2003
Posts: 10,019 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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I Live Here
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Frostbitefalls MN (Rocky&Bullw...
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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.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2401461
11/10/17 04:53 PM
11/10/17 04:53 PM
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Joined: Oct 2015
Posts: 570 UK
rb446
mopar
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mopar
Joined: Oct 2015
Posts: 570
UK
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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
Last edited by rb446; 11/10/17 04:53 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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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2401462
11/10/17 04:55 PM
11/10/17 04:55 PM
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Joined: Jan 2003
Posts: 8,035 Tulsa OK
Bad340fish
master
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master
Joined: Jan 2003
Posts: 8,035
Tulsa OK
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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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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2401478
11/10/17 05:21 PM
11/10/17 05:21 PM
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Joined: Oct 2015
Posts: 570 UK
rb446
mopar
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mopar
Joined: Oct 2015
Posts: 570
UK
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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.
Last edited by rb446; 11/10/17 05:31 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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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: rb446]
#2401485
11/10/17 05:33 PM
11/10/17 05:33 PM
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Joined: Dec 2013
Posts: 4,704 Wichita
GY3
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master
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Wichita
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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, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs. 10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: crackedback]
#2402497
11/12/17 02:10 PM
11/12/17 02:10 PM
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Joined: Jan 2003
Posts: 27,421 Balt. Md
383man
Too Many Posts
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Too Many Posts
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Balt. Md
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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
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2402552
11/12/17 03:15 PM
11/12/17 03:15 PM
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Joined: Aug 2003
Posts: 43,303 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,303
Bend,OR USA
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383 motors need to rev to go fast at the 1/4 mile tracks Short stroke motors need all the help you can give them 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 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.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: grancuda]
#2402643
11/12/17 06:36 PM
11/12/17 06:36 PM
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Joined: Jan 2003
Posts: 14,514 So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
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So. Burlington, Vt.
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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 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: fast68plymouth]
#2402686
11/12/17 08:05 PM
11/12/17 08:05 PM
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Joined: Oct 2015
Posts: 570 UK
rb446
mopar
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mopar
Joined: Oct 2015
Posts: 570
UK
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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.
Last edited by rb446; 11/12/17 08:11 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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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: rb446]
#2402845
11/13/17 12:51 AM
11/13/17 12:51 AM
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Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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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 Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: 4.10 Gears vs 3.91/3.73/3.55 - effects on 1/4 times
[Re: fast68plymouth]
#2402853
11/13/17 01:08 AM
11/13/17 01:08 AM
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Joined: Feb 2005
Posts: 4,320 Prospect, PA
BSB67
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master
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Prospect, PA
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........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.
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