BPF, could be. We had one of the first swept tail examples, I can't remember what it had on the wings, but I thought they were injected. Unlike the Continental IO540, they were the absolute sh!ts to start when hot. One of the boys crashed that one landing one night in a snowstorm. The company then bought a couple more, but had them re-engined with 8 cylinder, 400 hp engines which made a honest machine out of it but by that time I'd moved on. It was the only airplane I ever really disliked.