There are two general directions one can go on JY TBI installs.
Option #1: Install a system from a JY vehicle that had a motor similar to yours and adjust things such as fuel pressure, injectors and idle speed to get it to run decently on your engine.
Option #2: Install a system from a JY vehicle and reprogram the chip for your particular vehicle.
They are both valid ways of getting to the same destination. But the tips and tricks required are often different. Thus, using a 454 (2" bore) throttle body may work for one person, but not another, depending on their methods.
1987 Grand Wagoneer, slightly longer than stock.
Don't mess with me. I once killed a living hinge.