I only have HO 4.0L & 258ci flexplates, both measure ~2.695" I.D., they are a "stamped tang" style hub-hole....not the easiest to get a precise dimension on. The bolt pattern is on a 3.75" circle, the bolt holes do not appear to have any shifted away from the 60°-on-center, the bolt hole diameters are .547"(4.0L) & .532"(258ci). As far as crank flange to ring gear & friction face offset/spacing is concerned, can't help with that, need an actual flywheel in You hands for that.
Honestly, go to a site that sells flywheels & see if You can bring one up along with a blueprint/spec diagram.
Best of luck!
EDIT; I meant to add, that's not a promising set of dimensions, there would have to be some serious "re-engineering" involved, so...
starting from scratch is likely the best policy..peace!
Jim K6