me most about your post is the A/F ratio. If it was around 13, meaning 13 parts air to one part fuel then you are running dangerously LEAN. And if you get that other leak fixed it's apt to run even leaner...that's a recipe for disaster. And to (not) answer your original question, different dynos measure horsepower and load differently. I'm sure one of the more learned and technically oriented members of the forum can explain the dynamics of the differences. Take care of that lean condition. Good luck, Mark