Hey, my dad has a 99 gt and he finally wants more power. Actually he just wants more power to keep up with the motor im building ( a 99 - 01 cobra motor) but any ways i can find 3 valve motors cheap low milage and direct swap with the kit. My question is how reliable are the motors? What hidden problems are they hiding? I know from working in a shop that 3 valve motors blow plugs out the head, is it the same with the mustang 3 valve motors? Any intake problems? It has good power stock and a 4 valve is only 15hp more. If i go the 4 valve route im gonna do the same build im doing now which is a teksid block from a lincoln out in the junk yard and just find 99 - 01 cobra heads and intake complete. I'd imagine both ways to go run around the same cost maybe 1500 bucks me doing all labor.