Yep, I understand that too. Maybe the paracidic loss is in the longer stroke having too speed up the piston at a higher rate to reach full speed than the short stroke does. I dont know and I dont think we will ever know for sure how much more drag is there in the longer stroke. No way to see or measure it. I think it's just theory right, but it is interesting. Then again with a longer rod you would have more weight. Does one cancel the other out? Does the oil or lubes make all this a non issue?