Buffalo Engineering makes the best adapter plate to mate the TH700 trans to the stovebolt engines. They also sell a modified flex plate (flywheel) that allows the original equipment starter to be retained. Yes, you will need to alter the motor mounts to the mid-engine position and a single mount at the rear of the transmission. The Turbo 700 is extremely sensitive to throttle pressure (TV) cable adjustment, and it requires some sophisticated geometry at the throttle linkage bell crank to make not only the total movement of the cable but also the rate of travel correct. There are a few websites with detailed information on that subject, but someone else will need to link to a reference to them. When the TH-700 was new, it got such bad publicity that GM changed the name- - - -not the transmission on later models. The "4L-60" (without the "E" suffix) is the same transmission, just with a few upgrades!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!