IMPORTANT!
When you install the new one, torque it evenly, 25% at a time, in a cross pattern, on the crank first. Then, MOST IMPORTANT, hand-start all 4 nuts on the convertor, then lightly snug up #1, turn it 180 degrees and recenter it on the studs and snug up #3, then turn 90 degrees to snug #4 and finally turn another 180 degrees and snug up #2. ALWAYS turn it in the forward direction, don't back it up. Turn to #1 again, torque it down, then repeat as above, same pattern.
Someone in the past didn't do this on yours - it caused sideways torque loading in one section of the flexplate, which fatigued it until it broke.
5+ years ago, I rebuilt my engine and used the old flexplate - everything was fine until the tranny wore out 20,000 miles later at 205,000 miles, so I had a local reputable shop rebuild it. BUT, they installed the flexplate wrong, tightening #1, #2, #3 and #4 in that order. It broke just 3,000 miles later. They overcharged me $350 to install a new one. It went 8,000 miles and now it, too, is broken. They installed it the same way: #1, #2, #3 and #4.
An old, retired Ford man told me how to do it the right way. It seems the same flexplate is used for 260/289 engines, so there's no way a 170/200 could ever break it from sheer power.... I'm about to re-replace it myself, so I can drive trouble-free for another 200,000 miles.
