Some Basic Questions for the Experts on Transmissions

[maclonchas]

Folks,

I got overruled on taking on a GTM build as my wife says taking on other people's problem is a recipe for home issues. I do not need that at this stage of my life. :). I am seriously considering a Type 65 Coupe new build as my Mk4 is about ready for paint in the next few weeks with Jeff Kleiner. My plan would be to do a build starting next year, but I have a lot of questions after reading multiple threads on the forum. First off, I have seen several builds now with LS engines and that is something I wanted to do when I started the MK4. Part availability was not my friend and had to switch to a Boss 347 (thanks Mike Forte).

My desire would be to go with an LS6 engine from a Corvette Z06 mated with a 4Lxx Automatic Transmission. if not the LS6, then an LS3 would have to be used for the build. Can anyone confirm whether the AOD 4Lxx works with the Coupe build and if the transmission and engine mount locations have to be modified. I have seen several threads that stipulate the 4Lxx is smaller width than the T56 so that should not be an issue for the transmission tunnel.

Last question for now is the connection of the AOD to the rear end. I would prefer using a 3 link Moser 8.8" if possible. Does FFR support that driveshaft/coupler? If not, what about the IRS configuration?

Thanks

Bill

[Jeff Kleiner]

Bill,
Can't help with the question of whether the trans will physically fit but the transmission output shaft and driveshaft has to be addressed. Like the late Mustangs they use a stationary companion flange and flexible Giubo joint rather than a slip joint into the transmission. This can be converted to do away with the rubber Giubo and accept a conventional U-joint. Adapters are available from Sonnex as well as others:

https://www.sonnax.com/parts/3868-3-bolt-adapter-flange-yoke-kit

You'll then have to have a driveshaft fabricated that incorporates a slip yoke:

https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQh1HWCuxrfyzY8EAuqQblvz_bUyWjl2 LwqYA&s

It's kind of hard to fit this all in on a short roadster driveshaft but not difficult to accomplish on the Coupe thanks to the longer wheelbase.

None of this is directly supported by FFR with off the shelf parts for either the 3 link or IRS.

Jeff

[gbranham]

I had a 2017 Z06 before I bought my MkIV kit. Mildly built with around 730FWHP. Can't imagine that powerplant in a Coupe or Roadster, but it sure would be fun!

[Its Bruce]

I had a 2017 Z06 before I bought my MkIV kit. Mildly built with around 730FWHP. Can't imagine that powerplant in a Coupe or Roadster, but it sure would be fun!

The LS6 is a publicized 405HP.

I will always suggest the IRS. I also went custom
length driveshaft to make use of 1350 u joints on both ends.

[maclonchas]

Thanks everyone for their inputs and suggestions on this topic. It seems that the AOD for an LSX might be a reach at this point and really only available on the truck and hot rods from Factory Five right now. I will look more closely at the TKX and T56 which seemed to be solved in previous builds.

[Kbl7td]

Ditch the LS6. Doesn’t really make sense. There are loads of LS3 out there or L99. ANY driveshaft can be made by the driveshaft shop. Mine was custom made for the LT1/TR6060 combo.

[Jeff Kleiner]

Ditch the LS6. Doesn’t really make sense. There are loads of LS3 out there or L99. ANY driveshaft can be made by the driveshaft shop. Mine was custom made for the LT1/TR6060 combo.

Yep, You can buy Camaro 6.2 dropouts with the 6L or 8L six or 8 speed automatics (or the TR6060) all day long. The legwork on converting the driveline is already done. You'd simply have to have the shaft made.

Jeff