There is a wonderful piece of software called "X-Plane" which is a flight sim that lets you put to the screen in realtime things such as power output, fuel flow etc. It's easy enough to change the power output of the engines so you could choose a plane (perhaps the C-152) and fit the 2 different engines to it.
You could then test-fly the planes (in standardised conditions of course), noting down the power it’s producing at different stages of flight (I think you can output the data as a file, but i'm not sure how that works).
Anyway - that's the best I can come up with. I hope it’s of some use if you can’t find real data.
X-Plane can be found at <A HREF="http://www.x-plane.com" TARGET="_blank">www.x-plane.com</A> but you'll need a fairly beefy computer to run it (demo is free but quite big).
Out of interest, what is the project about - and what is it for? It sounds fascinating!
Feel free to send me an e-mail if there's anything I might be able to help with (rpm settings for a C-152 or if you can’t run x-plane for instance!)
Dupre.