I do not know if those are being reproduced any more. I have come across them, supposedly new, but rather pricey.
If its similar to the F body pieces you could swap over the cam arm and first section of linkage from one without that. There is a difference in the shaft on the motor though so you'll have to do some modifications to the mounting hole in the cam arm. A little filing should work.

Not the clearest picture, but...cam with large bushing on left, non-bushed on right.