What truck? Onroad or offroad racing? Real racing or backyard stuff?
Real racing, a 3.5 turn motor is too much motor. for bashing or street fun, it may be good for some fast action. Lipo or NiMH?
If just backyard fun or bashing, really consider the Castle Mamba Max Pro + 5700kv motor. I just put in a 4600kv and Mamba Max into a T4 and it's much better performance-wise than an aging Novak 10.5 I pulled out of it and even the 7.5 Velocity that I had run previously. The 4600 is a good motor for racing too for off-road mod 2wd truck class.