727 w/ GV vs A518

[Spartan040]

Debating between these two transmissions for my Challenger build, advantages and disadvantages to both? What about possibly adding a GV unit to the A518? Engine is going to be a 440/512 stroker

[CUDA JAS]

good discussion here.

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

[mrob]

Both have pros and cons. I'll throw out a few of my own observations and maybe more people will chime in:

1) You'll need a JW Ultrabell if you plan on using the A-518. The Ultrabell itself costs around $400. You need to cut off the existing bellhousing in order to install the Ultrabell. NOTE: this is only necessary for a big block.
2) When using the A-518, you'll need to cut your driveshaft around 3 1/2 in. AFAIK, you need to cut the driveshaft more with the GV, so getting the driveline angles will be more critical.
3) Both transmissions will require some amount of tunnel massaging. See the sticky in this section for the A-518 swap. AFAIK the GV needs some tunnel clearancing behind the torsion bar crossmember (where the driveshaft is).
4) No transmission mount modification necessary with the GV. With A-518 you need to cut your trans mount and modify it.
5) Cost? Hard to say - if you can find a good used A-518 core and do most of the fabrication yourself, it could end up being be cheaper then the GV. AFAIK the GV unit costs around $2800.

Hope this helps. FYI - I already pulled the trigger and bought an A-518 for my Cuda.

[Spartan040]

Well, as of now I know next to nothing about transmissions, so whatever I decide, I may want to get a performance shop to do the finicky and tricky stuff. Part of me is intrigued by the idea of basically having an 8 speed transmission by putting a GV on an A518, but it would be more complicated to do that than simply putting a GV on a 727. Is the A518 superior, or is it basically a 727 with an OD?

[Spartan040]

How reliable is an A518 compared to a 727? Will it handle the same kind of power that a 727 can? I've heard that the A518 is superior because it has a lock-up converter, and that this further decreases RPMs and prevents slippage?

[BFM_Cuda]

Part of me is intrigued by the idea of basically having an 8 speed transmission by putting a GV on an A518,

I'm not 100% sure, but I don't think you can put a GV on a 518, since you have to replace the tailshaft on a 727 to mount the GV, and the tailshaft houses the overdrive unit on the 518. Don't quote me on this, I just have not seen that application yet.

How reliable is an A518 compared to a 727? Will it handle the same kind of power that a 727 can? I've heard that the A518 is superior because it has a lock-up converter, and that this further decreases RPMs and prevents slippage?

I think they are comparable as far as reliability and power considerations. You need to check the model year transmission to see if its a lockup converter or not. The early ones are non lockup, regular converters. Its easy to tell by looking at the overdrive wiring plug, 2 wire plug is non lockup, 3 wire is lockup converter.
And yes, when the converter locks up, you have no slippage in the converter and lower RPMs even more.

[Spartan040]

I'm not 100% sure, but I don't think you can put a GV on a 518, since you have to replace the tailshaft on a 727 to mount the GV, and the tailshaft houses the overdrive unit on the 518. Don't quote me on this, I just have not seen that application yet.


I think they are comparable as far as reliability and power considerations. You need to check the model year transmission to see if its a lockup converter or not. The early ones are non lockup, regular converters. Its easy to tell by looking at the overdrive wiring plug, 2 wire plug is non lockup, 3 wire is lockup converter.
And yes, when the converter locks up, you have no slippage in the converter and lower RPMs even more.

GV makes a unit for the A518, and good, I guess I've decided on that then