Hey, Im thinking about buying a set of used Edelbrock 60379 Performer Heads for my 5.0 mustang. The guy said they will need machineing due to the fire ring on the head gasket and obviously they will need rebuild new seals and what not. But hes asking $500 doesnt seem like a bad deal up here in canada.

Can you guys think of ANY cons when it comes to these heads. And my Mustang has a full BBK exhaust, E303 cam and about 30 km on fully rebuild engine that i finished last week. Also how much HP will these heads add?