anybody here ever done a LS1 and used a Chevy Auto instead of a T56. I know everyone will probably say its stupid but I'm looking for consistency in my times. cant find anything on using an Auto. Don't know if it's ever been done, or Discussed . Any input

 

the original Dynosty car had a glide.

It can be done and is straightforward. Quamen ran a th400 i think behind his LS swap. no fitment issues.

the 6l80 is a lot longer, but you have to buy a custom driveshaft anyhow

 

I was wondering the same thing a few days ago.

 

I'm not sure if it will even fit

 

The 4L60, 4L80 and 6L80 are huge. This is why most people just use a TH400.

 

The 4L60 and 4L65 are the same length as the T56, but the crossmember mounting point is around 3" closer to the motor.
If you go on the Sikky web site they say their Drive shaft works for the 4L60.
The 4L80 is bigger and longer.
I've been thinking about putting a ls2/4L65e combo out of a GTO in mine, but with the weak Canadian dollar, it would cost me a lot.

 

Length is the same, width is not. They require floor "massaging" to fit it most cars that weren't designed for them.

 

Here is a pic of the 2 trannys side by side.
Sikky says there headers work with the 4L60, so width there shouldn't be an issue there. Maybe the pan may cause some issues.

 

Sorry to beat on but I am very interested to understand all the issues with doing this.
I put a LT1/4L60E in an 87 RX-7 pictured below and I miss the power.
The car was very consistent and drivable. I drove it 3 hours to the track on drag radials and ran 11.87@116.
I found the auto easier on the car as well.

 

On the T56, where the gearbox bolts to the bellhousing, it's tapered in there. The 4L60E bows outward, making it much wider there. That's the spot where I've seen floorpan contact. It's not a huge issue if you're willing to "clearance" the floor a bit with a BFH.