You can get replacement motors from Mato and other sources. If it's not listed on his website, send him an e-mail. They are 385s but exactly which ones remains open in debate. I saw a fellow once run Graupner Speed 400s in his Panther with El Mod, however, the El Mod guys could not guarantee it wouldn't blow the boards because the motors are rated for 7amps, the boards 5.

Is it possible the first step or two on the HL board is blown? Have you run the motor directly off a battery and compared it to another?