You said you set the timing to the proper sepc but it sounds to me like it is retarded.With the engine running have the dist clamp bolt just loose enough enough to turn it to the place where it runs best for now as a test to see if you are working on the right area.Please be aware you can have the index marks on the harmonic balancer not where they should be.It is not uncommon for an old balancer (or not so old) to have the outer rim with its marks, slipped from the proper relation to the hub which is keyed to the crank.
See if timing by ear will help it and then we can tell you where to go from there.
We can reestablish the proper relationship for the marks and we can verify the cam timing without a teardown.
