727 w/ GV vs A518

Author Topic: 727 w/ GV vs A518  (Read 3591 times)

Offline Spartan040

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727 w/ GV vs A518
« on: March 11, 2016 - 10:22:01 AM »
I'm debating between bolting on a GV unit on to a 727 (whenever I finally start my project), or using an A-518. I know the A-518 has a lock up converter so it drops the RPM's even more. But, the GV unit on the 727 is almost like having 6 gears, vs 3+OD on the 518. I'd like if I could have the best of both worlds and maybe use a GV on the A-518? Then I could have both lock-up and overdrive. Which of these options would be best for both driveability, efficiency and performance? Are there any better options I'm not aware of?

Also, how does the OD in the GV unit work? Is it automatic or do I have to hit some button to go into OD in each gear?
« Last Edit: March 11, 2016 - 10:25:36 AM by Spartan040 »




Offline dfrazz

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Re: 727 w/ GV vs A518
« Reply #1 on: March 11, 2016 - 10:39:07 AM »
I would vote for GVOD.  One thing to note if you have an X or H pipe, you will need to modify this to be further back.  TTI offers an H and X-pipe specifically for the GVOD if interested.  http://www.ttiexhaust.com/Footnotes/61.htm

Offline CUDA JAS

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Re: 727 w/ GV vs A518
« Reply #2 on: March 11, 2016 - 11:03:47 AM »
good discussion here.

http://www.cuda-challenger.com/cc/index.php?topic=107627.0

I think it depends on how much work you want to do.

74 'cuda 360/727



Gearhead: car nut, automotive enthusiast, one who loves hot rods, muscle cars, hot trucks, burnin' rubber and neck snapping performance. 

Just call me a gearhead!

Offline Chryco Psycho

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Re: 727 w/ GV vs A518
« Reply #3 on: March 11, 2016 - 12:02:37 PM »
I lean more towards the A518  the GV is heavier & adds length to the tailhousing which shortens the driveshaft & can create some driveline vibe , otherwise the GV is a great piece

Challenger - You`ll wish You Hadn`t

Offline Mopar73340

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Re: 727 w/ GV vs A518
« Reply #4 on: March 12, 2016 - 11:56:40 AM »
I'm debating between bolting on a GV unit on to a 727 (whenever I finally start my project), or using an A-518. I know the A-518 has a lock up converter so it drops the RPM's even more. But, the GV unit on the 727 is almost like having 6 gears, vs 3+OD on the 518. I'd like if I could have the best of both worlds and maybe use a GV on the A-518? Then I could have both lock-up and overdrive. Which of these options would be best for both driveability, efficiency and performance? Are there any better options I'm not aware of?

Also, how does the OD in the GV unit work? Is it automatic or do I have to hit some button to go into OD in each gear?


I have the GVOD behind my 727. Best improvement I've made to the car. There are two places you will have to clearance the tunnel slightly. The unit will shift with the flip of a switch or you can leave it in auto mode and will engage about 45mph. It is a good OD unit. I would not try and shift it between each gear on the 727.
73-Challenger 340 727/GearVendors Auto
73-Challenger 408 Pistol-Grip 5-speed

Offline 360FISH

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Re: 727 w/ GV vs A518
« Reply #5 on: March 16, 2016 - 01:35:36 AM »
I love my 518! 
Was a great investment for me...  one of the very best upgrades I've done.
 :cooldancing:
1973 ‘Cuda   Semi-Pro Touring
360 SB - 518/OD auto tranny - FAST EZ EFI - Edelbrock Fuel sump - HHR fan
Hella H4 headlights on relays - 97 Dodge Avenger seats - Chin spoiler - Bumpers pulled in to ’72 offset

Build: http://www.cuda-challenger.com/cc/index.php?topic=74674.0

Offline EbodyMod

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Re: 727 w/ GV vs A518
« Reply #6 on: March 16, 2016 - 12:26:16 PM »
I have the GVOD behind my 727. Best improvement I've made to the car. There are two places you will have to clearance the tunnel slightly. The unit will shift with the flip of a switch or you can leave it in auto mode and will engage about 45mph. It is a good OD unit. I would not try and shift it between each gear on the 727.
[/quote]

How much clearance is slightly? I am planning on one and getting ready for paint but cannot buy the unit yet. Should I try to compensate for it before paint or am I ok with a few small dimples like their instructions say?

 :wavingflag:
:wavingflag:  Quit being offended by everything, I am sure you are doing something that upsets me, but I am not complaining about you!!! It is a free county get over yourself!

Offline CUDA JAS

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Re: 727 w/ GV vs A518
« Reply #7 on: March 17, 2016 - 09:19:19 PM »
I want to go with a 518...I figure I can get the cost down quite a bit vs the GV.

Finding one seems to be the hard part, we at least a non-lock up one.  But I might get to the point that I consider a lock up. 

Jason
74 'cuda 360/727



Gearhead: car nut, automotive enthusiast, one who loves hot rods, muscle cars, hot trucks, burnin' rubber and neck snapping performance. 

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Offline Katfish

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Re: 727 w/ GV vs A518
« Reply #8 on: March 17, 2016 - 10:01:53 PM »
You want the lock-up.  It's like having a 4.5 speed auto.
Tranny works less and runs cooler when it's locked.  Converter slippage can be as much as 7-8%

I absolutely love my 518, 2500 RPM is 80mph with 3.73 gears.


Offline Mopar Mitch

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Re: 727 w/ GV vs A518
« Reply #9 on: March 18, 2016 - 02:06:00 PM »
Doesn't the install of a 518 require major mods/cutting/fabrication to the crossmember?  I'm unaware if there's a pre-made crossmember offered... is there?  Any tunnel mods required?   Truly, I'd favor to retain all-Mopar whenever possible.
Autocross/road racers go in deeper... and come out harder!

See  MOPAR ACTION MAGAZINE, AUGUST 2006 ISSUE for featured article and details on my autocross T/A.

Offline 360FISH

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Re: 727 w/ GV vs A518
« Reply #10 on: March 18, 2016 - 03:48:17 PM »
Doesn't the install of a 518 require major mods/cutting/fabrication to the crossmember?  I'm unaware if there's a pre-made crossmember offered... is there?  Any tunnel mods required?   Truly, I'd favor to retain all-Mopar whenever possible.


Hey Mitch,
No mods to the tunnel...   a cross member can be had from Rory still...  it's based on the one here... 

http://www.cuda-challenger.com/cc/index.php?topic=84774.0

BTW - I love your car

 :burnout:
1973 ‘Cuda   Semi-Pro Touring
360 SB - 518/OD auto tranny - FAST EZ EFI - Edelbrock Fuel sump - HHR fan
Hella H4 headlights on relays - 97 Dodge Avenger seats - Chin spoiler - Bumpers pulled in to ’72 offset

Build: http://www.cuda-challenger.com/cc/index.php?topic=74674.0

Offline Mopar73340

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Re: 727 w/ GV vs A518
« Reply #11 on: March 19, 2016 - 03:20:28 PM »
I have the GVOD behind my 727. Best improvement I've made to the car. There are two places you will have to clearance the tunnel slightly. The unit will shift with the flip of a switch or you can leave it in auto mode and will engage about 45mph. It is a good OD unit. I would not try and shift it between each gear on the 727.


How much clearance is slightly? I am planning on one and getting ready for paint but cannot buy the unit yet. Should I try to compensate for it before paint or am I ok with a few small dimples like their instructions say?

 :wavingflag:


I installed the GVOD back in 2009 so I will have to assume it is still the same.

There is a small area at the top of the case you will have to clearance for and one where the 90* speedometer drive exits. A 3 pound hammer and a few taps should take care of the top of the tunnel and a small amount on the side for the speedometer.
« Last Edit: March 19, 2016 - 03:23:31 PM by Mopar73340 »
73-Challenger 340 727/GearVendors Auto
73-Challenger 408 Pistol-Grip 5-speed

Offline Mopar Mitch

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Re: 727 w/ GV vs A518
« Reply #12 on: March 20, 2016 - 10:18:17 PM »
T/Anks 360fish!... and for the extra backtrack on the install.
Autocross/road racers go in deeper... and come out harder!

See  MOPAR ACTION MAGAZINE, AUGUST 2006 ISSUE for featured article and details on my autocross T/A.

Offline Spartan040

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Re: 727 w/ GV vs A518
« Reply #13 on: March 23, 2016 - 09:00:51 PM »
So far I'm liking the sound of the 518, even without a GV behind it. I'm assuming I want the hydraulically operated one and not the electronic version? What parts are required besides the tranny itself to make this work?

Also, has anyone ever heard of TCI Auto? They have a 6 speed version of a GM 4L80E that looks interesting

Offline 360FISH

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Re: 727 w/ GV vs A518
« Reply #14 on: March 24, 2016 - 01:53:07 AM »
So far I'm liking the sound of the 518, even without a GV behind it. I'm assuming I want the hydraulically operated one and not the electronic version? What parts are required besides the tranny itself to make this work?

Hi Spartan 

This has info on the 518 swap...
http://www.cuda-challenger.com/cc/index.php?topic=84774.0

Enjoy!

Alan
1973 ‘Cuda   Semi-Pro Touring
360 SB - 518/OD auto tranny - FAST EZ EFI - Edelbrock Fuel sump - HHR fan
Hella H4 headlights on relays - 97 Dodge Avenger seats - Chin spoiler - Bumpers pulled in to ’72 offset

Build: http://www.cuda-challenger.com/cc/index.php?topic=74674.0