Since nobody bothered to give you a defintive answer to your using the 70 Surpass on the World Models P51 let me say this. It is a perfectly suitable engine for the airframe. I helped another RCU member from the SF Bay Area break one in on a WM P51 several months back and it was flying dependably after running 2 tanks on the ground for break n and to adjust the high end (low end was perfect from OS). The plane flew excellent - no problems and no complaints.

Alex where do you fly in the Bay Area? Perhaps you can come over some time to see how it flys, looks and sounds?