If it's not too late you should put some washout in the wings and keep the plane as light as possible. I had a kit built TF P-40 with a DLE 20 and Century Jet air retracts. The plane weighted 12.5 lbs and was an absolute b----- to fly. If you pulled up too quick, turned to sharp, etc it would snap. Once on down wind the engine just quit. I left the gear and flaps up and tried to do a 180 to belly land on the grass runway. About half way around it could tell is was on the verge of a stall, snap. Had to level the wings and land straight ahead in the corn. Only minor damage. I had over 120 flights on it and don't know how I didn't total the thing. After that I took all the hard ware out and sold the plane for a display model.
I later got the TF 60 size P-40 ARF. Powered by the same DLE 20 with Lado electric retracts. It is about 11.5 lbs and has wing washout. Completely different bird. Flies much easier and better. No tendency to snap in what I consider normal warbird maneuvers. Lands slower and easier, but still need to land on the mains and keep a little power all the way to the runway.
Good luck with the P-40. Let us know how it is going.