The 302 in my 62 Galaxie had a stock 2-barrel intake and corresponding carburetor. Recently, I was fighting with an intermittent vacuum leak when the motor was under a load and had concluded that the issue was probably in the intake. Since I had to pull the intake anyway to reseal it, I decided it was the perfect opportunity to install a 4-barrel Edelbrock performer intake and corresponding 4-barrel carburetor.
Before The Work Begins
There is nothing more frustrating than getting part way through a project only to find out that you are missing something. To avoid this problem I run through the project in my mind and make a list of everything I am going to need. For this project I purchased a Felpro intake gasket kit which had two intake-to-head gaskets, a new distributor o-ring, and 4 pieces of scrap cork. (We will get to that later) I also purchased a carburetor gasket, a new thermostat, thermostat housing gasket and a new temp sending unit. The temp sending unit and the thermostat that were installed with the 2-barrel intake could have been re-used with the new intake. However, I felt it was better to spend $12.00 now and have new parts that probably wouldn’t have to be replaced in the near future.
Keep in mind when doing a small block Ford intake swap that the heads on your motor may require one of two gaskets. Some of the early 351 heads have an extra intake mounting bolt and that requires a different gasket. A good rule of thumb is match the gasket to the heads. If your head has a square shaped water jacket opening then you need a square opening in the gasket. If the head has an “L” shaped water jacket, then you need an intake gasket with an “L” shaped water jacket opening.
Prep Replacement Intake
When getting an intake you have the choice to either get one new or used. To save money, I purchased a used one on Ebay. The good news was that the seller didn’t bother cleaning it so I got a better price. The bad news was I had to clean it. Prior to cleaning the intake, any plugs, studs, vacuum ports, sending units or anything else installed on the intake should be removed. In my case, since the intake was used, the best technique for removing the parts threaded in to the intake, was to flip the intake over and apply a liberal amount of penetrating oil around the threads and give the oil 24 hours to do its job. This helps reduce the chance of damaging the threaded ports on the intake.
Once all the extra parts have been removed, soap, chemicals and/or abrasives can be used to clean the intake.
With the intake prepped, I installed the thermostat and housing, the temp sending unit, a vacuum outlet and the intake runner plugs. I could have easily installed all these parts with the intake on the car but I find it easier to get to everything with the intake on the bench, especially the lower thermostat housing bolt.
Marking Plug Wires
Once you have the intake prepped, you are almost ready to begin disassembly of the current set up. But before you do that, there are a couple simple things you can do to make reassembly a little easier. The first thing is to mark the spark plug wires that will be disconnected so that they can be reinstalled later with out having to refer to a shop manual.
Index The Distributor
The second preparation step that will insure easier assembly is to index the distributor. I found the easiest way to do this is to make sure the harmonic balancer is clearly marked at the degrees where the timing is currently set. In other words if the motor is currently set with 10 degrees of timing advance, then make that mark very visible on the balancer. I put a red mark on one side of the timing mark and a yellow one on the other to make it easier to see in the picture. I then turned the engine so that timing mark is on the timing indicator.
By doing this, the distributor rotor will be in the #1 position. On the Duraspark distributor in my car the magnetic pickup was perfectly lined up with trigger and rotor. This was perfect as it provided a reference as to how the distributor needed to be reinstalled later. If you have a points distributor, you will need to mark the inside of the distributor to indicate what direction the rotor was pointing.
With everything prepped, labeled, and indexed, disassembly can begin. I always start will the coolant lines because there will always be some coolant spills. Leaving all the other parts installed limits the places that the coolant can spill into. From there I start in the front and work my way back. When disconnecting a Duraspark distributor it is best to use a small screw driver to loosen the connection prior to pulling the connectors apart.
The distributor should then be removed very carefully making sure that the oil pump drive rod does not come part way out with the distributor because it can fall back in to the distributor opening and end up in the oil pan. I then disconnect any carburetor linkage, vacuum connections, fuel lines and wires. From there you have the choice to either remove the carburetor from the intake or remove the carburetor and intake as one unit. I like to remove the carburetor from the intake because it reduces the chance of damaging the carburetor.
The only things left holding the intake in place are the intake bolts and any glue used to seal the intake when it was installed. Sometimes, lightly tapping the intake with a rubber mallet is all that is required to loosen the intake, but other times it takes a little more persuading. I had to wedge the end of a pry bar against the back of the water pump and then place the shaft under the thermostat housing to apply enough pressure to get the intake loose so it could be lifted off.
Clean And Prep Gasket Surfaces
With everything disassembled, there is one more important step that must be done, clean and prep the gasket surfaces. I start by placing an old clean towel in the lifer valley. This is for two reasons, first it soaks up any coolant left in the lifter valley, and second it keeps gasket material and other debris from getting in to the lifter valley. A gasket scraper can then be used on all the gasket surfaces to remove any pieces of gasket left behind. Once the gasket material has been removed, I like to use a scotch bright pad to finish cleaning the mating surfaces and then very carefully remove the towel make sure not to spill any gasket pieces in to the lifter valley.
Putting It All Back Together
As you begin the reassembly process, it is a good idea to place the intake/head gaskets in place and do a dry fit of the intake to make sure there are no unforeseen fitment issues. Also note that the gaskets are directional and should be marked as to which side of the gasket goes against the head.
When you start putting it all back together, it is a good idea to put a thin layer of RTV on the heads around the water jacket, and on intake/head gaskets around the water jackets to help prevent leaks especially on older parts where the mating surfaces might be slightly pitted. Keep in mind that once the RTV is on the heads and gasket you need to get the intake on in less than 10 minutes so that the thin layer of RTV does not set-up too much.
Earlier I referred to the cork gaskets that came in my gasket kit as “4 pieces of scrap cork” The reason for this is most people do not recommend using them. The biggest issue with the cork intake gaskets is they tend move out of position when you torque down the intake. Most often if there is a vacuum leak under the intake it is because of those gaskets. It has become common practice for both armatures and professional mechanics alike to dispose of the cork gaskets and use RTV in their place.
The process of using RTV is very simple, start by putting a 3/8” thick bead of RTV on the front and rear gasket surfaces. Make sure that each end of the RTV bead overlaps the intake/head gaskets, give the RTV 5 to 7 minutes to set up, and then place the intake on to the engine.
The only challenge to using RTV in place of the cork gaskets is the intake needs to be set directly in to place with out any movement forward or backward. Correctly setting the intake on the motor can be done with a steady hand but to make it easier I recommend using guide studs. Prior to beginning my project, I made 4 guide studs out of 4 bolts that were about 1” longer than the intake bolts.
With the studs in place I gently set the intake on to the engine and began installing the intake bolts, finger tight and after most of the bolts were in I removed the guide studs and installed the remaining 4 bolts.
The next step is to lightly tighten the bolts down with a nut driver to avoid over tightening them. It is important to note that there is an order that intake bolts must be tightened in. If it is a stock intake, the order should be in a shop manual, but if it is an aftermarket intake, you need to get the information from the manufacturer.
One at I time, I tightened each bolt as tight as I could get it with a nut driver. By the time I came back to the first bolt I was able to tighten all the bolts a little more due to the intake settling in to place. From there it was just a matter of using the torque wrench and the tightening order to tighten all the bolts down to 18 foot pounds. As I was using the torque wrench, I went through the sequence twice because just as with the nut driver when you tighten the intake down it settles and the first bolts tightened loosen up.
With the intake installed, I was able to reinstall all the other parts I had removed during disassembly including the distributor, carburetor, hoses and any other connections.
Dealing With Fluids
The RTV needs at least an hour to set up before you fire up the motor and tune the carburetor. This is a good time to address the motor's fluids. The radiator needs to be topped off and the oil MUST be changed. It really doesn’t matter how careful you were when removing the original intake, some coolant will spill in to the lifter valley and consequently drain in to the oil pan. There is no way to avoid this and the oil must be changed after the install.
Enough coolant went in to the lifter valley that when I first pulled the oil plug only coolant came out.
After about a quart of coolant came out oil began to drain out of the pan.
After about a quart of coolant came out oil began to drain out of the pan.
Once the fluids are in and the oil had been changed, the idle mixture screws on the carburetor can be set to one and a half turns and the motor will start. From there it is a basic tune up with carburetor and timing adjustments. When you start the motor for the first time with the new intake, watch for coolant leaks. Any leaks outside the motor will be visible, but the only way to see any leaks under the intake into the lifter valley is to check the oil several times over the first couple of days of use. If the amount of oil in the engine seams to be increasing, then you have a coolant leak raising the oil level. If not, then the install was a success and you can use the car.