Hello, I am thinking of swapping out the turbo 350 in my 70 GTO and replacing it with a 700R4. Any tips? What will need to be changed and altered? I am under the impression that a 70 GTO is the same more or less as a 70-72 Chevelle. THe GTO currently has a 427 BBC and a TH350 trans.

Thanks for your help, Kyle.  

u might have to remount the the trans crossmember that supports the tranny and ther could clearance problems with the bell housing. not too sure on that one/ check the lengths of the trany cause you will probably need a new drive shaft.  

u might have to remount the the trans crossmember that supports the tranny and ther could clearance problems with the bell housing. not too sure on that one/ check the lengths of the trany cause you will probably need a new drive shaft.  

How should I go about determining how much I'll need to shorten the driveshaft?

Thanks for the help thus far, Kyle  

Here is a good page i have found for transmission lengths.(http://www.hotrodders.com/forum/transmission-information-30771.html)
About 3/4 the way down the page it shows the different transmissions and there overall length as well as length from bellhousing to trans mount. Hope this will help a little.  

Most common way to measure drive line length is from the rear seal on the trans to the center of the universal joint on the differential yoke. Give this measurement to your drive line guy and tell him how you got it and he will cut it to the proper length. ALWAYS measure with the new trans in place, NEVER cut an estimated amount.  

I've just recently done the switch from the Turbo 350 to the 700R4.(great transmission!!!)

If you have the 9" tailshaft on the Turbo 350; there is only a 1" difference in the legnth of the transmission.
You will need to pay particular attention to the TV Cable adjustment as this is a critical adjustment controling the pressure to the valve body.
Too low a pressure translates to a destroyed transmission.

You will need to drill new crossmember bolt holes 2" back on the frame.

Other than that the installation was very simple.