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low gear set, or converter
#965124
04/03/11 12:03 PM
04/03/11 12:03 PM
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Joined: Jan 2003
Posts: 864
St Paul MN
73swinger
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 864
St Paul MN
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Currently running a 340 727 in a 73 Dart Swinger, about 400 HP at crank, full interior, mostly strip 1.9 60ft times.
current converter is 9.5" 3600 flash stall.
I shift and cross the line at about 6000 rpm.
Question is: what would provide better gains??
upping the stall to 4200? or putting a low gear set in the 727 ??
A 408 is the future plan for motor (1 or 2 years)
Chris Schwartz
73 Swinger 340 12.451 @ 108.78
73 Gold Duster, needs a plan.
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Re: low gear set, or converter
[Re: 73swinger]
#965126
04/03/11 12:24 PM
04/03/11 12:24 PM
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Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
tubtar
master
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master
Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
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More gear will kick up your r.p.m. at the stripe........I don't know how much more is in there.
The low gear set should help the 60's.
With an engine that makes power where I'm guessing yours does , more stall would be of marginal benefit.
For where it sits now , I like the low 1st. gear option.
And I agree with Fred's assessment about building based on what if's.
With more torque on tap via the stroker , the low gear set might not be the benefit it is with a smaller motor unless you know you can get it hooked.
It might want to bust them loose at the hit.
You can then juggle tire height to compensate.
And fall into a series of trade offs.
You really want to build for what you have and minimize guessing and compromising to make it work.
Some stuff will work with both too , but with the stroker , I think the converter makes more sense.
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Re: low gear set, or converter
[Re: tubtar]
#965127
04/03/11 12:40 PM
04/03/11 12:40 PM
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Joined: Jan 2003
Posts: 864
St Paul MN
73swinger
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 864
St Paul MN
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John/tubtar
my 340 runs good to 6200, I don't want to twist it any higher. Just want to try and maximize the power and RPM range I have now. I think its going to have to go 2 more seasons.
Chris Schwartz
73 Swinger 340 12.451 @ 108.78
73 Gold Duster, needs a plan.
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Re: low gear set, or converter
[Re: 73swinger]
#965128
04/03/11 12:54 PM
04/03/11 12:54 PM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
John/tubtar
my 340 runs good to 6200, I don't want to twist it any higher. Just want to try and maximize the power and RPM range I have now. I think its going to have to go 2 more seasons.
A low gear set changes the launch and really nothing
after that(it will increase your down track RPM some)...
you can figure that a conv is for the launch also
unless it has greater slippage which will turn more
RPM every where... also the conv will stall higher
when/if you go to the 408ci(about 300-400 rpm based
on the torque differences)... you need to figure out
where the max torque is now to tell you what direction
you really want to go... but in a heavier car the low
gear usually helps out ... just some things for you
to help figure it out
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Re: low gear set, or converter
[Re: MR_P_BODY]
#965129
04/03/11 01:06 PM
04/03/11 01:06 PM
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Joined: Jan 2003
Posts: 864
St Paul MN
73swinger
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 864
St Paul MN
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Launch and 60 foot is what I need.
I MPH at 107/8 , but only ET 12.6 on good days.
Car definetly pulls the top end better than the bottom.
And I have played with launch, and carb tune to get better 60 foot times, but am at a wall there.
Chris Schwartz
73 Swinger 340 12.451 @ 108.78
73 Gold Duster, needs a plan.
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Re: low gear set, or converter
[Re: 73swinger]
#965130
04/03/11 01:13 PM
04/03/11 01:13 PM
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Joined: Aug 2003
Posts: 43,223
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,223
Bend,OR USA
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Quote:
Launch and 60 foot is what I need.I MPH at 107/8 , but only ET 12.6 on good days.Car definetly pulls the top end better than the bottom.And I have played with launch, and carb tune to get better 60 foot times, but am at a wall there.
The 2.77 low gear set is a great way to improve 60 ft. times in a lot of low power(slower than 11.00 ET that hook good  )cars. Can you or are you willing to switch to a 904 with a low gear set? There is ET and MPH there I don't know if you can have a 727 converter converted to be used in a 904  Anybody do that or know? I know NHRA stocker racers, both BB and SB that picked up .18 or more by switching to the 904 trans. 
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: low gear set, or converter
[Re: 73swinger]
#965131
04/03/11 01:40 PM
04/03/11 01:40 PM
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Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
S/ST 3040
master
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master
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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My  ...... Small engines don't like the bigger RPM drop of the low gear sets, especially in a heavier car. If you are happy with RPM at the stripe, leave rear gear alone. My vote goes for an 8" 5000 stall converter. 2.77 low gear set is probably more expensive than the good converter. Once you make the switch to a good 8" converter, you'll never look back. 
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Re: low gear set, or converter
[Re: S/ST 3040]
#965132
04/03/11 01:41 PM
04/03/11 01:41 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
My ......
Small engines don't like the bigger RPM drop of the
low gear sets, especially in a heavier car. If you are
happy with RPM at the stripe, leave rear gear alone.
My vote goes for an 8" 5000 stall converter. 2.77 low gear
set is probably more expensive than the good converter.
Once you make the switch to a good 8" converter, you'll never look back.
 forget the rest
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Re: low gear set, or converter
[Re: Cab_Burge]
#965133
04/03/11 01:42 PM
04/03/11 01:42 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
master
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master
Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
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I have had a 904 converter changed to fit a 727. Several parts have to be swapped in the internals. Switching the pump drive to the smaller one for a 904 might be an issue. There is a modified 904 pump made that uses the 727 pump drive. Not sure about the stator support.
I think a 904 would be a benefit also.
I have ran the low gearset and thought it was the cat's meow on a slower combo. Later had more motor and wore out that tranny. Switched over to make a race in a hurry. The 244 ran the same numbers across the board.
The 2.44 is pretty low compared to what is offered in the glides.
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: low gear set, or converter
[Re: 73swinger]
#965134
04/03/11 01:49 PM
04/03/11 01:49 PM
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Joined: Jan 2003
Posts: 5,991
Anoka County, MN
Leigh
master
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master
Joined: Jan 2003
Posts: 5,991
Anoka County, MN
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Race only? If so, yes, the stock X type heads are mostly done at 6000. I went with 5200, 4.56 and 97" circumfirence. 6200 at stripe for 4,000 passes. Have you priced that gear set? It was $700 ten years ago. The 904 idea would be more valid, as that trans can also go behind the bigger motor. Street/strip? I haven't a clue.
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Re: low gear set, or converter
[Re: 73swinger]
#965136
04/03/11 02:01 PM
04/03/11 02:01 PM
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Joined: Jan 2003
Posts: 32,394
Quicktree
I Win
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I Win
Joined: Jan 2003
Posts: 32,394
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Quote:
Quote:
Quote:
My ......
Small engines don't like the bigger RPM drop of the
low gear sets, especially in a heavier car. If you are
happy with RPM at the stripe, leave rear gear alone.
My vote goes for an 8" 5000 stall converter. 2.77 low gear
set is probably more expensive than the good converter.
Once you make the switch to a good 8" converter, you'll never look back.
forget the rest
OK option 3, please tell me more. What and why do I gain with 8" converter? For information purposes, this car does see street time,sometimes 100+ miles on freeway. I have a trans cooler. current converter is 9.5" PTC. New converter all together is possible, What do you 8" guys think would be a good stall or flash for a streetable combo.
an 8" converter gives you more torque multiplication. 5000-5200 on the street wont be a problem
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Re: low gear set, or converter
[Re: 73swinger]
#965137
04/03/11 02:02 PM
04/03/11 02:02 PM
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Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
Leon441
master
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master
Joined: Nov 2004
Posts: 4,330
Lynchburg, VA
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4,400 stall.
When driving the converter will only slip a lot when under a lot of load. Ran one for years and drove a lot of miles. And one huge hill to climb on the way home every night.
Career best 8.02 @ 169 at 3050# and 10" tires small block power.
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Re: low gear set, or converter
[Re: Quicktree]
#965141
04/03/11 02:36 PM
04/03/11 02:36 PM
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Joined: Jan 2003
Posts: 864
St Paul MN
73swinger
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 864
St Paul MN
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Quote:
I forgot to add, going with an 8" may cause traction issues. you will need a good set of shocks and a working suspension..
I forget what my current shocks are, but they are long enough, and I have a set of Ranchos on the shelf. Stock leafs, and snubber currently work well. I have spent most time and money sorting out transmission back for efficency with what I have for motor, gears, and wheel well room.
Future upgrades always possible. Caltracs may be needed at some point, but this year is just trans, or converter.
Trying to get the most from the 340, at or under 6200 RPM
Maybe I am totally off base, or expect too much. I'd be happy getting this heap to run in the 12.20 area.
Last edited by 73swinger; 04/03/11 02:37 PM.
Chris Schwartz
73 Swinger 340 12.451 @ 108.78
73 Gold Duster, needs a plan.
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Re: low gear set, or converter
[Re: 73swinger]
#965143
04/03/11 03:17 PM
04/03/11 03:17 PM
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Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
tubtar
master
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master
Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
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904 from Lofgren .........around 2,000.00
Now , you need another converter.
Converter for the 727 .........decent starts around 600.00
Should be around a grand for top of the line.
Low gear set .........525.00 at A&A
I have a 1978 class C motorhome with a 360 and 727 ......... it probably has a low 1st. gear.......definitely a four pinion planetary I would think.
But I am not sure.
It will be getting parted soon I think ......... maybe you could toss a re-build at it and give it a try if it has the right innards.
It has just over 110k on it and runs like a watch , but rust has gotten on top of it a good bit.
I bought it years ago from a guy who " needed drugs more than he needed a motorhome "
He inherited it from his Dad.
I used it a lot for about six or seven years , but it has been sitting for the last couple.
Let me know if you think it has the right guts and we can probably work something out.
Last edited by tubtar; 04/03/11 03:18 PM.
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Re: low gear set, or converter
[Re: Leigh]
#965146
04/03/11 04:53 PM
04/03/11 04:53 PM
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Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
tubtar
master
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master
Joined: Nov 2009
Posts: 3,082
St. Paul , Mn.
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Quote:
The low gear set wasn't in any oem 727. I researched this to the nth degree years ago in between customers at Bloomington Chrysler. I also used the transmission numbers that were International Truck. The 4 pinion front planet isn't necessarially the final answer. 
O.K. surprising , but good to know.
The four pinion is stronger and more desirable if I understand things , but I didn't think it was contingent on ratio.
They were truck and H.D. pieces if I recall , but I am still pretty new to the Pentastar world.
I guess I thought that a small block lugging that big tub of motorhome around would get a low 1st . gear as a matter of principal.
There are aftermarket low gear sets for the 727 ........ these come from later O.D. transmissions ?
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Re: low gear set, or converter
[Re: 71cuda]
#965150
04/03/11 08:47 PM
04/03/11 08:47 PM
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Joined: Dec 2004
Posts: 1,489
St. Louis Mo.
10 o to go
"Happy Don"
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"Happy Don"
Joined: Dec 2004
Posts: 1,489
St. Louis Mo.
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Low gear set also change 2nd gear also from what I've have .
I run low gear and a 8" 4400 T.A convertor .
Yes you can get them out of certain stock transmissions .
i believe I stepped up to a aftermaket one that A&A makes now .
I run low gear set and the Coan super sprag and trans brake in both trans now .
Like most say you need to be able to take the hit and traction .
DR
2009 418" build dan smith built
new 9.96 131.82
6.23 108
1.30 60 foot
best to date 9/15/09
8in 727 430 dana 2860 lb 3040 lb w driver
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