RE: Surging on Acceleration (again)
Ok, this may help or likely not.
Back in the early days of the P-70, I had a similar problem. Even had a flame out on the ground during takeoff at a meet because of it. I was told by JetCat the problem was caused by the fuel needles not being shaped correctly and/or positioned incorrectly. They thought it wouldn't happen in the air but it did and so does a P-120SE I'm flying now.
John Redman eventually fixed the engine (when I got around to sending it in) by re-bending the needles and such. Don't know the specifics but since he owns the place now, you might call and discuss your problem with him.