* Different bellhousing pattern: The 400ci engine in your Trans Am likely uses a different bellhousing bolt pattern than the 700R4 transmission. You'll need an adapter plate to mate the two. These are available from aftermarket suppliers.
* Torque converter: You'll need a torque converter specifically designed for the 700R4 and your 400ci engine. The wrong converter can lead to premature transmission failure.
* Driveshaft: The driveshaft length will likely need to be shortened or lengthened to accommodate the 700R4's different output shaft length.
* Crossmember: The transmission crossmember will need to be modified or replaced to properly support the 700R4.
* Electrical: The 700R4 is electronically controlled, requiring wiring modifications to integrate it with your car's electrical system. This includes the transmission control module (TCM) and appropriate wiring harness. You might need a standalone controller or adapt it to your existing system (if you have one).
* Cooling: The 700R4 has specific cooling requirements. You may need to add or modify your existing transmission cooler lines.
* Shift linkage/cable: The 700R4 uses a cable for shifting (though some use a linkage) rather than the linkages used in many TH350/400 style transmissions. You'll need the correct linkage or cable setup.
In short: While possible, this is not a beginner's project. It requires mechanical expertise, specialized tools, and a good understanding of automotive transmissions and electronics. You'll likely need to source several parts from aftermarket suppliers. Consider the cost of all these modifications before starting the project. It might be more cost-effective to consider a professionally built transmission or even an entirely different transmission swap that requires less modification.
