Thank-you, inside it has an O ring near the bottom. That makes it a Lock-up? It has the splines on the top edge of large sprocket, so that's high stall. Inside is 5 3/4" deep, bottom of crank hub, outside depth is 5 7/8".
The back side, flexplate lug, area, looks modern, not rounded like the 70's 11" type. (see photo's) The hub side is normal round, with no large weights on the flat band, one tiny balance shim tacked.
The other difference is the symmetrical bolt pattern.
Have a new flex plate that can easily be made symmetrical by an drilling an adjacent hole, to the offset one. I used a old plate to mark the new hole.
The crank hub is new and "centers" the converter for no vibration. So the plate just drives the trans. With some plate wiggle before its bolted in, is normal, correct?
It looks like 23 splines on the small sprocket. What, used that in 1984?