ORIGINAL: Motorboy
I has the old catalog who was in the box for OS engine. There are two versions of OS FSR 61, one with ABC (Really ABN) and one with ring.
I can upload the photo of catalog of the OS FSR 61 later..
Yes, there was an ABN version of the FSR. I did end up owning and flying the ABN OS .61 VF. It was strong and I had no problem with a peeling liner. It had a lot of flights on it while blowing through its OPS muffled tuned pipe. A nice engine.
Ed Cregger