Need help I am putting a new engine I a 02 gt and I can’t seem to get the flex plate situation sorted out. You see the engine I got as a replacement has a 8 bolt crank but the 02 has a 6 bolt therefore I cannot just swap the Flexplate over. Well I bought a new 8 bolt Flexplate that supposedly fits 96-2015 mustangs but nope that didn’t work then I got on LMR and found another one but it said not compatible with a 12” torque converter. Well I have no clue how big that thing is but I’m pretty sure it’s 12” because that’s also what LMR says fits the 02 gt. So at this point I have resorted to seeing if I can take a 6 bolt crank and put it in the engine that has the 8 bolt crank the. valve covers Are different on the engines so Romeo/Windsor I’m sure y’all know and I’m pretty sure the engine with the 8 bolt is from a 98 gt. Please help I really don’t know where to go from here. Thanks
98 GTs have a Romeo engine, like your 02 (just not upgraded heads/cams); I've had mine apart enough to confirm this. 8 bolt is a Windsor engine, and was in the Mustang from 99-00, which is probably what you should be looking for.
While technically possible to swap cranks, I wouldn't without having a machine shop check everything. Typically as an engine heats/cools/turns, things tend to warp/wear, especially on the bottom end. The chances of everything being in spec between both cranks and the new block aren't great, and will affect the longevity of the engine. Honestly, if you can't find a working 8 bolt flex plate (I don't know the 4R70W enough to advise there), you would probably be better off selling that engine and buying a Romeo one; these engines are cheaper than the work to swap cranks.