Sorry that this has nothing to do with your question.....but why are you switching to the GT-40 aluminums? Are you getting a good deal on them? If you're just paying normal price.....honestly, you can get way better heads out there for roughly the same price. A magazine I read like 6 months ago did a comparison and the GT-40P (I believe thats the designation for the alums) didn't fair very well against the other aluminum heads...the Edelbrocks made like 30-40 hp more on a motor making 300+ horses on stock heads. Just food for thought.
Have you tried calling around? Hell, I'd call Ford....and maybe Summit and Jegs. Their technical departments tend to be pretty good, as long as you pretend you're going to buy the parts from them.
Plan on 3 days to do the job if you haven't done it before.
Day one gets the heads off in 4-6 hours. The A/C Compressor comes off with lines still connected. Mark all the electrical, smog and vacuum lines with tags to help you remember where to re-connect them.
Day two gets all the gasket surfaces scraped off extra clean and the heads dropped off at the machine shop if you are going to have them reconditioned. Time here is another 4-6 hours. Whatever you do, don't skimp on cleaning the gasket surfaces. New gaskets need to seat against bare metal and not the residue left from the old gaskets in order to seal leak free. This is the most time consuming and tiresome part of the job. Look for little things that need to be replaced like the short hose from the thermostat hosing to the water pump, damaged vacuum lines and hose clamps that are rusted or broken.
Day three starts when you get the heads back from the machine shop. This is the time to pick up all the little odd pieces you found needing replacement on your day two inspection/cleanup. Plan on 6-8 hours to reinstall the heads and reconnect everything. Plan on an additional 2 hours to troubleshoot/adjust everything.
Now for some practical tips:
Plan on cutting the thermostat to water pump hose, or removing the thermostat housing. Also plan on removing the distributor to get clearance to remove the intake manifold. Remove #1 spark plug, stick your finger in the spark plug hole and crank. When your finger gets air moving past it, stop cranking. Turn the engine until the timing marks line up with the pointer. Now you can pull the distributor out.
You'll need new head bolts - get ARP bolts ($40) or studs ($93, maybe more). All the bolts get antiseize under the bolt heads, and everything but the short head bolts get it on the threads. You need Teflon pipe dope or ARP sealant to coat the threads of the short head bolts. The short bolts go into the water jacket and will seep coolant if you don't use the sealant.
My favorite trick that saves time and effort is the stay in place gasket. Be sure that you scrape (don't use a wire brush) all the old gasket material off, then clean all the surfaces with acetone or MEK.
When the surfaces are clean, use weather strip adhesive on the head to manifold surface, and on the side of the gasket that mates to the head. Follow the instructions on the tube or can and when it gets tacky, press the gasket down on the head.
Clean the area where the rubber rails mount to the block in front and in the rear with more acetone or MEK and do the same trick with the weather strip adhesive that you did to the heads.
Coat the rubber seals and the gasket area around the water passages with lots of Blue Silicone gasket sealer and put it together. Walla! No leaks and no gaskets that shifted out of place.
If you reuse the injectors from your old setup, a repair kit is available from most auto parts stores if needed. Coat the injector body "O" rings with oil before you use them and everything will slide back together.
For iron heads, clean the combustion chambers with a wire brush in an air or electric drill. I used a scraper for the pistons. I don't like to use the wire brush on pistons because it will remove metal very easily.
Change the oil once you get everything back together. Once the engine is up & running, run it for 1-2 hours and change the oil.
Tools: a good torque wrench is a must have item. A razor blade scraper that holds a single edge razor blade from Home Depot or Ace hardware is another handy thing. Get a Chilton or Haynes shop manual - you'll need it for the bolt torques and patterns. The intake manifold has an especially odd pattern. You'll need access to a timing light to set the timing after you re-stab the distributor.
Consumable parts for EFI only:
Fuel injector seal kits with 2 O rings and a pintle cap (Borg-Warner P/N 274081) are available at Pep Boys auto parts. Cost is about $2.74 per kit. The pintle caps fit either injectors with a pin sticking out the injector end or 4 with more tiny holes in the injector end. The following are listed at the Borg-Warner site ( http://www.borg-warner.com ) as being resellers of Borg-Warner parts:
Most of the links above have store locators for find a store in your area.
Use motor oil on the O rings when you re-assemble them & everything will slide into place. The gasoline will wash away any excess oil that gets in the wrong places and it will burn up in the combustion chamber.
I have GT40Y303 heads (aluminum), but they're sized for the 7/16" head bolts. If your heads are set up for the larger bolts, you should use the bushing to properly center and seat the bolt head. And if you're going with a 2.02 intake valve, even with the stock cam, I'd measure p to v clearance to be sure. Jrichker's got you covered on the swap.
The 'best' way is the way you're most comfortable with. Below is the way I prefer to do it - finally wrote it up and saved it because people kept asking.
Positive stop – obtain an old spark plug for the Ford engine – most of us have at least one laying around. Put it in your vice, and with a tool of destruction you deem appropriate – cut off the ground tip and bust up the ceramic around the center electrode. Keep pounding to get the ceramic and center electrode removed so you’ve got a good ¾” or so of hollow space inside what used to be the ‘business’ end of the spark plug. If you happen to break the ceramic on the other end of the spark plug, don’t worry about it. Once you’ve got a nice hollow space in the tip of the plug, take a 5/16” tap, and cut threads inside that end of the plug. I found that diameter to go right in without any drilling required. Once you’ve cut threads, screw in a 5/16" bolt about 1.5” to 2” long. Then take your hack saw and cut the head off the bolt. Wouldn’t hurt to take your file/grinder and dress up the freshly cut surface so no sharp edges or shrapnel enter the combustion chamber. Also clean up the threads on the plug so that it easily screws into and out of the plug hole.
Determining TDC – remove the passenger side valve cover. Remove rockers from the intake and exhaust valves on the #1 cylinder. Rotate the engine (socket on crank bolt) until the #1 piston is down the cylinder on the intake stroke. Unscrew the spark plug in that cylinder, and replace it with the positive stop you just made. Only screw the positive stop in hand tight. Install your cam degree wheel and pointer (no easy task in some cases as harmonic balancer and other accessories will have to be removed). You may want to remove all spark plugs at this point because it will make it easier to smoothly turn the engine over in small increments. GENTLY rotate the engine clockwise until the piston comes to rest against the stop. Note the degree wheel reading. GENTLY rotate the engine in the opposite direction until the piston comes to rest against the stop. Note the degree wheel reading. TDC is exactly half way between these readings. Calculate where that position is on the degree wheel, remove the piston stop from the cylinder, and rotate the engine to TDC as you calculated it.
Degreeing the cam – install the camshaft in the straight up or dot to dot position to start with. Set your dial indicator up over the #1 intake valve lifter or pushrod. Rotate the engine clockwise until the intake lifter/pushrod just begins to rise. Follow the dial indicator and stop the rotation when the lifter is at .050” lift. Take a reading on the degree wheel. It should match your cam card information for the number of degrees at .050” lift on intake valve opening. For example, the cam card on an E303 cam says that the intake should be open .050” right at top dead zero – 0 degrees TDC. So if you rotate the engine until your dial indicator shows .050” lift on the intake opening, the your degree wheel should be pointing right at tdc. If you’re within a degree or two, then you can go ahead and check the .050” closing timing, as well as the opening and closing events for the exhaust valve. They should all match up with the cam card info within a degree or two. If, for example, at .050” you’re supposed to be at 0 degrees TDC (from the cam card), and after your dot to dot install you’re reading 4 degrees after TDC at .050”, then the intake valve is opening too late (4 degrees later than it should). To adjust this, you need to make the intake open 4 degrees earlier (right at tdc), so you’ll have to advance the cam by 4 degrees. To do this you slide your indexed timing set off, you select the “4A” slot on the crank gear (instead of the straight up position), align it with the dot on the cam gear and reinstall. Remeasure as described above – you should now read .050” lift right at TDC. Many contemporary cams have assymetrical lobes – so I wouldn’t install the cam using the lobe centerline method – the centerline can be difficult to find. I recommend using the .050” lift timing events for the install – check all 4 of them to be sure the cam is doing what the cam card says it should be doing.
Drop valve measurement – now that the piston is at TDC (be sure you're at TDC during overlap - between exhaust and intake strokes) you can safely remove the valve springs on the intake and exhaust valves. I used an inexpensive KD tool for a small block Chevrolet (Blasphemy!). It bolts into the pedestal and has a crow’s foot that sits over the spring retainer. It’s nothing more than a pry bar. Be sure to screw the rocker bolt far enough into the pedestal to hold the tool. You (or your big friend Bubba) are going to apply significant force on the lever to compress the spring. A small magnet is invaluable for grabbing the keepers once the spring is compressed. Also, a couple of taps (lightly – careful here) with a hammer on the retainer can help free up the keepers. The valves may or may not drop down and touch the piston – be sure it’s at TDC to limit the valve movement. Set up your dial indicator over each valve. Rotate the engine to about 20 degrees BTDC. Now, in 5 degree increments, until you reach 20 degrees ATDC measure the distance between valve closed and valve touching the piston. You can move the valve up and down with your fingers, or if the seals are loose, up with your fingers, gravity will take care of down. You’ll have maps of closed valve to piston contact distances every 5 degrees from 20 BTDC to 20 ATDC for intake and exhaust. Rotate the engine back to 20 BTDC (back the way you just came – if you rotate the other way, the piston will drop all the way to the bottom and you’ve got valves dropping down into the cylinders – DON’T DO THAT!!) and set the dial indicator up over the intake and exhaust lifters (or pushrods if you don't have a dial indicator extension). Make the same measurements on both lobes – a map of lift on intake and exhaust lift at 5 degree increments from 20 BTDC to 20 ATDC. Multiply the lift times the rocker ratio. That is valve lift. At each 5 degree point, subtract valve lift from the valve closed to piston contact measurement. That is your piston to valve clearance. It should be more than .080” on intake and .100” on exhaust for engines revving less than 6500 rpm. As your rpm increases, your clearance should increase. If you’re revving to 8500 rpm, you probably want on the order of .125” to 150” on intake/exhaust to be safe.
One other tip on holding gaskets in place. Jrichker's adhesive approach works. Here's another approach - I go to the hardware store and obtain bolts as follows: 2 the same size as the valve cover bolts; 2 the same size as the short upper intake bolts; 4 the same size as the lower intake bolts; 2 the same size as the header bolts. I cut the bolt heads off and slot that end so I can get a screw driver in it. For example, when setting the lower intake, I screw those 4 'studs' into the 4 corner lower intake holes to act as temporary dowels. They hold the gaskets in place, and provide a guide for you to lower the manifold into place perfectly. Once you've started a couple of the other bolts, you can remove your temporary dowels, and replace them with the bolts. It works great especially when you're working by yourself.
If you decide to use clay, be sure you mock up a solid lifter - the spring/plunger in a stock one will throw your measurements off. Some folks will suggest using test valve springs instead of the solid lifter - be careful. Even the forces/friction of new valve seals has been enough in my experience to depress the lifter plunger and throw the clay measurements off.
The easiest way to check p v clearance is with clay in my opinion. Get a cheap light spring from the parts or hardware store and install it in place of the regular valve spring. I bought a single solid lifter to use also. Just put some lube on it. You can try it with a regular lifter, or you can put a regular one together with the something that takes up the freeplay. Put some clay in the valve relief area, and carefully assemble the head with light torque and turn the engine over a couple times (assuming you do not feel and binding). Pull the head and check the clay. I was surprised to find plenty of clearance to the bottom of the relief, but the radial clearance was tight.
Well worth doing. Do at least on intake and one exhaust.
To rd's point - radial clearance can only be measured with clay. But for those of us with large valves (like your 2.02's) that won't enter the relief anyway, it's a moot point. It'll hit the piston top first.
Most folks use clay. I prefer the other method because I'm never certain if I got the clay in the right spot, or if I sectioned it in the thinnest spot. I'm also concerned about altering the thickness of the clay when removing it, sectioning it and measuring it - in general, handling the clay after the impression is made has the potential to alter it. And there's no accurate way of measuring it without handling it.
Having said all that - I think it's a matter of personal preference. Use whichever approach floats your boat. Just be sure you degree your cam first - cam timing impacts the clearance. And of course, for later cam swaps, the drop valve method can be used to check clearance without removing the heads.