The K&B 6.5cc engines has no baffle on the pistons. Those are .40 displacement engines as well and the DDD head may very well fit them. I don't know as I don't have one at this time to try it on.

If I remember right K&B might have made what looked like a K&B .40 4011 engine. But it had the newer more robust crankcase front end on it. I am thinking it was the model 4050, 4060 ABC version. But I could be wrong. I think they used something more like the PDP porting on the engine similar to the K&B Twister engine. It is in between being a cross flow scavenged and a Schnuerle ported engine.

I also have one of those DDD diesel heads for a K&B .40 too.