I thought I'd share my experience and document this for others. I'm not going to go into WHY the ATTS was removed, and if you are interested, I suggest you search. This question is asked all the time, a brief search will tell you all you need to know.
First, thanks to Ian Clendaniel (clendaniel) who proved this could be done and first documented it. Here is his original post:
buh-bye ATTS.
I think that what I have come up with is a slight improvement to with respect to strength. It might be harder for some people to make.
First, the basic problem is that the SH has mounting holes for the ATTS unit and removing it requires installation of the base intermediate shaft... which it has no provision for. Here is the base block:
Note the 3 holes in the upside-down "L" pattern.
Now the SH:
The circled hole was a "blank" boss that I drilled and tapped to add another mounting point for the plate. The problem with the hole patterns is multiple. First, the holes aren't in the right place. You need to "make" these holes by making a plate to cover the existing SH/ATTS holes, then drill that to accept the intermediate shaft. Second, the bosses on the SH are 1/4" closer to the block than the base (they need to be built out 1/4" for the shaft to line up correctly). This is handy since you can buy steel plate in 1/4" thickness.
The last problem is that the upper-left mounting tab on the intermediate shaft interferes with one of the ATTS bolt holes... meaning, if you use that hole on one you can't use it on both.
To fix that problem help insure that the shaft doesn't move and is secure, you need to cut and relocate that tab on the intermediate shaft. Ian cut the ear off and welded it in place in the new location, having one bolt go through the shaft and plate and into the block. The other two go directly into the plate (but not the block). He then used the other hole in the SH block to hold the plate down. You can see his setup here:
And in the thread posted above...
I was doing this operation on an ITS racecar that is putting down in the ballpark of 200WHP and gobs of torque... with race rubber and an LSD and final drive (in the new base tranny). I wanted something a little more beefy. This was my solution:
I had to file down the "blank" boss (circled in the picture above) and drill and tap it, but it resulted in another mounting hole for the plate. On top of that, instead of relocating the cut tab on the intermediate shaft, I just welded on a piece of steel onto the side and drilled holes to line up with the two mounting points on the SH block... so two bolts go through the intermediate shaft and the adapter into the block. I think this provides a considerable amount of rigidity to the intermediate shaft and an additional safety margin.
For anyone that's interested, here's an Autocad .DWG of the plate:
http://www.marcuccimotorsports.com/j...pter_plate.dwg
and some pics of the plate and intermediate shaft work:
Note that instead of welding on nuts on the back of the adapter (to mount the shaft) like Ian did, I welded on a piece of steel flat and just tapped them both. I ground down the bottom of it (where it is shiny) to keep from interfering with the block. There is only I think about .3" of clearance between the plate and the block on the lower bolt hole, so you don't have much room to work with.
All said and done this was a LOT of work. I couldn't find anyone that had taken measurements, and the SH block was still in the car (making prototyping difficult). I came up with the dimensions by measuring the block and prototyping in Lexan.
The dimensions in the drawing are only approximate... I would recommend enlarging the holes some to allow for proper fit. If anyone wants to take more accurate measurements and provide them, I'll be glad to update the drawing.
Linear Mode
