67 Idler Arm Question..

Yes between castel nut and tab. I could tighten properly but nut was too far down the threads, below the hole for cotter pin

If the nut was too far on the threads then the washer wasn't thick enough. I went through this in 1996 with a '67 Barracuda that I bought. The car was overall in decent condition, but had a sloppy idler. There are no washer. Put a thick washer on and had no more problems with a sloppy idler. I only kept that in a few years. The next time the car went together was with a home built DC k-member and a 383...