Engine Kit, GX390/420, 420cc, +.200 Billet Crank, 88mm Forged Piston Our Price: $923.00 Hop Up Kit, 420 Predator OHV & 13/15hp Clone, Stage 4 Our Price: $1,149.00 Hop Up Kit, 440 Duromax, Mud Motor Kit, Stage 4 Our Price: $1,281.00 Engine Kit, GX270, 292cc (+.160) Stroker, R (2 to 1 Gear Box Cranks) Our Price: $519.00 Hop Up Kit, 420 Hemi, Stage 4 Our Price: $1,076.00 Header, RLV 3-Stage Pipe for Open & Modified GX200, 6.5 OHV, and 212 Predator Our Price: $38.99