GT40p heads

Its always better to take the heads apart yourself and see what they need to be done. Having a repair manual for this is very handy. Rent a valve spring compressor and take the valve springs off. Once you get them off make sure to make each valve so you know where each one went. Once you have the valves out you can see what condition the valve seats are in and will be able to tell if they need to be replaced. Check if they are corroded and measure if you have the tools. Also if you have a dremel or die grinder you can take some carbide burr bits and clean up the ports and bowls if you want to get into that, and remove the smog bump. At the very least though you can at least polish them yourself with some stones or something. If you dont have a die grinder or a dremel go spend the 60 bucks and buy a dremel its well worth the investment. A dremel will take longer but will work, dont go cordless though. Once you do that just clean them up the best you can, use brake cleaner, carb cleaner, anything you find that works best to get the gunk and carbon off the heads and valves. Once you do all that do some more measuring, check out the surface with a feeler gauge, check to see that the valves arent bent, cracked, warped, etc.

This is when a dial caliper, feeler gauge, and repair manual come in handy because the repair manual will have the specs of where everything should be and will tell you step by step what to check. THEN you can go drop them off at a machine shop, and tell them what you want done. You will save yourself a lot of money checking them yourself first and telling them what you want done, rather then just handing them over. They will have more knowledge than you so let them look them over again, but at least you wont let them rape you.

Buy new springs, and stem seals and give them to the shop. Have them check everything over again, if new seats need to be installed have them do that, if it needs to be resurfaced have them do that, and have them install the springs and check the install height, etc. If you do all that yourself and then give them to the shop I wouldnt expect to pay over 200 on machine work, unless they are real f'ed up of course, but ford heads for the most part should be in good condition unless they were overheated to the point of warpage.