Hey, 66:
Check out my new post "Ah, Sweeet Success". As long as you have the head off, try some of the mods.
When you get the valve job, study the work they did. If you have a sharp ridge around the edges of the valves (which is likely if they cut new seats or replaced your originals with hardened seats for unleaded gas), grind or file that sharp edge into a rounded profile. The sharp edge seriously impacts flow through the valves. Also, if they replaced the seats, remove the valves and carefully grind the back edge of the seat to match the port shape (be sure to stay away from the valve seat or you'll be back in the machine shop for repair). A large step here can cut flow by up to 25%. Mine came back with these 'steps' in 3 of the 6 intake ports after new seats were installed.
Get the head milled by .010" or .020". Each .010" removed reduces the volume by about 2cc, raising the compression ratio by about .5 or so (until the squench ridge is gone - then you have problems). Get some hardened washers to go on the head bolts when you reassemble, just to make up the missing height difference.
If you're handy with a grinder (like a Dremel tool), round the boss near the edge of the sparkplug in each head. There is a sharp ridge there that interrupts the squench mixing profile in these heads, at least on my 1978 head.
If you can afford the extra few dollars, have the machine shop "back cut" the intake valves (leave the exhausts alone - they're OK). This will increase the flow in the midrange, which is where these engines make most of their power, anyway.
Finally, get new hydraulic lifters while you've got it apart, and install them. Your old ones are leaky. New pushrods, too, if you can ante up the $28 that NAPA wants for a set. Between milling the head and installing new lifters, you'll get some extra valve lift for 'free', which will help wake up those ponies above 3000 RPM.
On reassembly, use ONLY the Ford steel head gasket or, if you can't find one, drop me a PM mail for one of the FoMoCo "C" type composite gaskets ($46), which are very close to the same thickness. If you use the steel gasket, get the Permatex "Copper" paint-on type gasket sealer, 2 cans. These head gaskets can be tricky to seal, so take your time when you do it with a steel gasket.
Good luck!
