I'm looking to do this so I can use the 4L60E swap crossmember since the mount points are roughly 2 inches farther back on the 4L60e than the 700R4. Has anyone one this or seen it done?

 

If I understand you correctly, i don't think you can do what you're thinking.
The early 4l60e is the same tail shaft bolt pattern as the 4l60/700r4 with the same mounting point.
The later LS style trans has a 6 bolt tail shaft mounting pattern and wont fit the early trans.
I just googled the images to see the differences

 

found this over on tech, don't know if it helps any or not. http://ls1tech.com/forums/automatic-...ail-shaft.html

 

Thanks for the link! It helps, kind of. I wish I had bookmarked where I read that there was an adapter. What year did they change the mount design to the 6 bolt? Was it 98? did they change the mounting points at the same time?

 

Alternately, can I just use my stock transmission cross member? From the research I have done, I don't think so because the LS motors sit back farther? Or do they only sit back farther because they're shorter?

 

The transmissions are interchangeable between 3rd and 4thgens without messing with the driveshafts and tq arms. soo nothing has really "moved"

 

if you want to retain the 700R4 and your stock crossmember, you will need 1" setback plates. LSX motors actually sit more forward than LT1's and earlier small blocks. third and 4th gen transmissions interchange only depending on the combo. the 4L60E with the bolt on bell housing the LSX motors use is longer than the LT1 version and the 700R4 as well as having the mount in a different place. if you are sticking with your 700R4, get 1" setback plates, use your factory motor mounts with them, and keep the 700R4 crossmember.

 

Thank you! That's the kind of information I was looking for. So I can use my stock cross member, I just need the set back plates for the motor mounts.

I picked these Spohn LS swap motor mounts up, will they work as the "setback" mounts that you're talking about? Or do I need the set back plates and these to work?

This Motor Mount thread here answered my questions. Thanks!

 

Now...to find someone that makes a tubular 700r4 cross member so I can better fit exhaust.