Milling Used Heads...is it needed?

you might not have to mill them but definetly get them checked so you dont have any problems

if they arent flat you wont get them to sit flush and you will blow head gaskets like there is no tomorrow. just get them checked out

I haven't talked to a machine shop recently, but they shouldn't charge you very much to check the heads with a straightedge. Well worth the money to have them checked and avoid problems later.

All you have to do is get a straight edge and lay it across the bottom of the head.Where the gasket is between head and block.Then get a flash light and see if you can see light thru any gaps.There is a tolerance if you have a feeler gauge.You could call a shop and ask the size of the feeler gauge and slide that size between the head and straight edge to see if it is warped to bad.Get a nice steel yard ruler for straight edge.I would not take it to a head shop and ask them for the simple fact if you are taken it to them you must want to fix it if they are warped.They might lie to make money.That is why everyone should find a local mechanic that has a small shop and go there only and build a relationship so you don't get taken for a ride.They do sell gaskets that will work with a minorly warped head.They even have different thickness gaskets to change compression slightly.