Originally Posted By Jim_Lusk
Neither case is true. There were some aluminum cases that were not OD and there were iron cases that were OD. There may not have been any factory-installed aluminum non-OD, but I'm not positive on that.

My son's Dart has a '75 iron OD case with '68 18-spline gears and standard A-body main shaft...


Never seen an alum NON OD outside of something sold over the counter thru Direct Connection ... maybe ??? ...

What model car/truck had an alum case non OD trans outside of a Superstock ???

running up my post count some more .