Casting Numbers/ Part Numbers

There always seems to be a little confusion concerning what these numbers mean, and, what the difference is between them. They are, after all, very similar. We'll start with the casting numbers. This is the number which is actually on the part itself. Some have it cast into the part, others have it stamped into the metal of the part, others, like wiring harnesses, have it ink or paint stamped on the part, and some don't have it physically present on the part at all.



Here's how that works. The first digit will be a letter which signifies which decade the part is from. 'A' is the forties, 'B' is the fifties, 'C' is the sixties, etc... The second digit will be a number, which indicates which year of the decade the part is from. So, if the first two digits are C1, this is 1961, D4 is 1974, B9 is 1959, and so on.



The third digit will be a letter, unless it's a part originally intended for something that didn't go into production until after 1970. Then, it could also be a single-digit number, but, not for a Mustang. This tells you which car line the part was originally designed for. This is just what it was originally intended for. They did not use car-line specific part numbers for the same part that was used in several different vehicles. A 66 model 289 hipo engine block will have the casting number of C5AE-6015-E on the side of it. This does not mean that the motor came out of a 65 Galaxie and was put in the Mustang by someone. On the small block V8s, the official "Original Intention" was for the Fairlanes on the 221/260s. That's why the early blocks have an O for the third digit, even though they were also using that motor in other cars, as well. That's why you see some blocks with an A for the third digit, like the 65/66 6-bolt K code motor. That particular variation was designed to be put in the full sized cars, but, was also used in Fairlanes, Mustangs and Falcons. The short version of this explaination is that the third digit tells you what the original drawings had written on the bottom of the page, but, the same part might be, and frequently was, used in several different car lines.But, what those digits actually mean is,

A---Full-sized Ford built after 1957

B---Bronco 70-73, Maverick 75-77, and Fairmont 78-83

D--- Falcon 60-69, Maverick 70-74, Granada 75-82, and, LTD 83-->

G---Comet 61-67 and Montego 68-76

H---Heavy truck 62-82

L---Lincoln 58-60, Lincoln Mark something 61-->

M---Mercury

O---Fairlane 62-68, Torino 69-76, LTD II 77-79

P---Autolite or Motorcraft 62-->

R--- Rotunda 62-69, Ford of Europe imports 70-->

S--- T-Bird

T--- Various trucks and Broncos

U--Econoline van

V---Lincoln Continental

W--- Cougar 66-72, Bobcat 75-80

Y--- Canadian Mercury Meteor 62-73

Z--- Mustang, Mustang II



The fourth digit is telling you what sort of part it is in a very general way.

A-- light truck part

B--Body or electrical component

C--Chassis

E-- Engine/powertrain

F--Electrical/ fuel system

P--Transmission/ axle

R-- Transmission/axle

S-- Truck Engineering

W-- Transmission/axle

X-- Muscle parts

Y Lincoln/ Mercury replacement parts

Z--Ford replacement parts



The first four digits will be followed by a hyphen, and then there will be a string of numbers, some having a letter thrown in just for fun, and then another hyphen. The stuff between the hyphens is what's called a group number. This tells you what the part is. 6015 between the hyphens means that this is an engine block. This might seem a pretty trivial bit of information to the person that is looking at the engine block, since they're looking right at it, but, to the people ordering the parts from the plant making them, which also makes a bunch of other stuff, it is very useful. On many parts, the casting number will not include the group number, because the person looking at the the number on the part would know up front that they have a carburetor in their hand. There's no need to stamp the 9510 on the carb just to make sure that the person with the gasoline dripping into his hand realizes that this is not a front bumper, but, a carburetor. The engineering number will have this, as will the replacement part number, though. The person at the warehouse processing the order has no idea what it is that I need.



After The 4-digit prefix, the group number, and, the second hyphen, there will be a letter. This letter indicates the design change level. That means that they started with a part, say, C5ZE-9600-A, which would be a breather assembly. They then change the design to include a fitting sticking out of the side of it. It becomes C5ZE-9600-B, they change the design again to put a longer, stiffer spring on the snorkel flap. It is now C5ZE-9600-C, and so on. This is purely for the sake of example, and are not actual design changes that are represented by these specific numbers. Let's say, for example, that I am needing a rebuild kit for my 2bbl carburetor, but, I am not sure if it's the original carburetor for my car, and, the I.D. tag for this carb has vanished in the haze long ago. I look at the driver's side of the carb, and, lo and behold, there is something stamped there on the base, near the front, and it says 6 D F. Clearly, this is not the entire part number, so, I will need to start filling in the blanks. I can tell that this carb is an Autolite 2100 from looking at it, so, it was built sometime in the sixties. That gives me C6 D F. I also know that, since this is a carburetor, the fourth digit will be an F, so, I now have C6DF F. Again, since this is a carburetor, the group number will be 9510, so, that gives me C6DF-9510-F, and, that is the complete part number. If my car happens to be a 66 model Mustang that came with a C4 automatic transmission and the thermactor system, this is the correct carburetor for that. The replacement part numbers and the engineering numbers will have the entire number, while, the casting number will frequently leave out the stuff that you can easily deduce by looking at the part itself.

Finding an electrical draw

If you find that your car's battery dies in a day or two when you don't drive the car, it could be that you have an electrical draw somewhere that is draining the battery. First, you would want to find out if this is actually what's happening. Start by charging the battery, and, with the positive battery cable connected and the negative battery cable disconnected, and take a volt meter and connect the positive probe of the volt meter to the negative battery cable and hook the negative probe of the volt meter to the negative battery post. With the doors of the car closed and the key in the 'off' position, the volt meter should read zero like that. If it it does indeed show zero like that, then you do not have a draw, and the problem is going to be the battery itself. If the meter does show voltage like that, something is pulling power when it's not supposed to. Fortunately, the list of suspects on a 65/66 Mustang is very short. You have the horns, the headlight switch, the emergency flasher/ cigarette lighter circuit, the ignition switch, and, if you have a convertible with a power top, the top switch. Also, the charging system has a wire that feeds into the hot side of the starter solenoid, so that, when the car is running, everything electrical is running off of the alternator/ generator instead of the battery, and, the ammeter gauge/ charge indicator light has a wire attached to this same post on the starter solenoid.

None of this stuff is on a fuse in the fuse box, except for the emergency flashers, so, don't start pulling fuses one at a time and checking to see if the draw went away. Unless the problem is with the emergency flashers/ cigarette lighter circuit, which it almost never is, the problem won't go away like that. Start by unplugging the alternator harness from the headlight harness and see if the draw went away. It's the three-prong connector down near the frame rail, kind of underneath where the battery is. If the draw went away, plug that back in and unplug the connector from the side of the voltage regulator. If the draw reappears, the problem is the alternator. Check and see if the black wire with the yellow stripe attached to the 'bat' post on the back of the alternator is shorting itself out on the alternator case somehow and, if yes, fix that. If it isn't, then you need a new alternator. If the draw does not reappear with the alternator harness plugged in and the voltage regulator unplugged, you need a new voltage regulator.

If the draw is still there when you unplug the alternator harness, then the problem is with one of the other systems mentioned, and, you will probably need to remove the instrument cluster to have a look back there. If you look in the april of 08 section here, there's a post on how to do that. It isn't difficult at all. Before you do that, though, go ahead and pull the emergency flasher fuse and see if the draw goes away. If no, go ahead and snatch the instrument cluster out. If yes, put the fuse back in and unplug the wire from the back of the cigarette lighter and see if the draw goes away. If yes, replace the lighter.

Once you have the instrument cluster out, disconnect the headlight switch connector from the headlight switch and check to see if the draw went away. If no, the problem is not with the lights or the horns, since the horn circuit gets it's power from the headlight switch. That leaves the ignition switch. You can check the wire that is hooked to the + or 'bat' post on the coil with the volt meter to see if it shows power with the key in the off position, but, if it does, you need to replace the ignition switch and you have to remove the instrument cluster to do that, so, it wasn't needless work removing the instrument cluster.

If the problem went away when you unplugged the headlight switch connector, plug the connector back in, and unplug the turn signal switch at the base of the steering column. If the draw goes away, the problem is something in the turn signal switch, most likely the horns. If the draw does not go away, unplug the connector behind the dash, kind of up above the fuse box , that the taillight harness plugs into. If the draw does not go away, the problem pretty has to be up front with the headlights or front parking lights/ turn signal lights. It isn't complicated, it's just a question of picking a place to start and working your way through until you find the problem. You don't want to fall into the trap that ensnares many, which is assuming that the problem is with component A and replacing it, only to discover that the problem is still there, so you then replace component B, C, D, etc... Don't start just throwing new parts at the car until the problem disappears. Take a minute to figure out what's actually wrong, and then fix that. You'll be much happier with this way of doing things in the long run.

64 1/2-only stuff in the underhood area

First, Let me start by saying that there are no Mustangs with 64 year model V.I.N.s. The first Mustang, 5F08F100001, was titled as a 1965 model car. All of these cars that we refer to as 64 1/2s are just really, really early 65 model cars according to the V.I.N. However, they have characteristics and features that Ford dropped at the end of the 64 model year. There were no alternator charging systems on 64 model Fords, and there were no generator charging systems on 65 model Fords, with the exception of the early production Mustangs, which they began building in early March of 64, instead of in July of 64, like the other 65 model cars. This is a pretty obvious difference between a 64 1/2 and a 65. This first picture is the generator of a 64 1/2 Mustang. It has this size-huge cast iron upper bracket, instead of the stamped steel bracket of an alternator car. This one is kind of hard to miss. Many of these cars, like mine, for example, have been changed over to alternators, though, so the absence of this generator and bracket does not mean that the car didn't originally come with it. I still have all of the generator stuff, in case I want to go back to trailered concours perfect, but, since it's my primary means of transportation, I have it on an alternator.

On the V8 cars, the 64 1/2s have what's called a five-bolt block, while the 65s have a six-bolt block. This is referring to the number of bolts that hold the bell housing onto the back side of the engine block. Here is a picture of a five-bolt bell housing. The arrows show where the bolts that attach it to the block are, and yes, you can see this with the motor and transmission still in the car, so, all that you have to do is open the hood, and then count them. There will also be some other bolts there, like the two that hold the starter on, the inspection plate at the bottom of the bell housing, but, the bolts that hold the bell housing to the block are pointing in the opposite direction of the others, so, it would be very difficult to get them mixed up.
On a 64 1/2, the brake light switch is on the front of the master cylinder, like the one in the picture, instead of hanging on the brake pedal inside the car, like a 65. You will also notice that the engine gauge wire harness has a couple of extra wires coming out of the firewall for the brake lights, so, the 64 1/2s also have a different engine gauge harness to accomodate the brake light switch.

This is a picture of the front passenger side of the radiator core support in front of the battery. You will notice those three slots in it that look like gills. The alternator cars don't have that. They just have those four slots over to the passenger side of the gills.

The flap indicated by the arrows hangs down a lot further on the 64 1/2s than it does on a 65. On the 65s, it only comes down about half that far. From the factory, this part is painted black, as is the upper area of the piece that this flap is a part of from the front edge of the cowl lip forward. This one is painted body color just so it stands out better. Again, if I ever go back to trailered concours perfect, I'll also fix that.

Many of the 64 1/2s had a cast iron crankshaft and water pump pulley set-up. Here they are, sitting beside the generator bracket. The one in the middle is the water pump pulley and the one on the left is the crankshaft pulley.

The generator cars had these great big horns mounted down on the strut rod brackets, instead of the smaller horns on the radiator core support that an alternator car had. There was also a horn relay mounted above the voltage regulator on the generator cars, instead of a wire coming straight out of the turn signal switch and going directly to the driver's side horn, then over to the passenger side horn, like the alternator cars.

This is kind of a small thing, but, it was a 'better idea' from Ford. You will notice in the picture that negative battery cable is attached to the inner fender area with a clip and a sheet metal screw. The generator cars had this, the alternator cars didn't. Even if the clip isn't there, there should be a hole in the car for the screw.

More to come later. (Insert smiley face here.)

Floor Mats

These are the different floor mats that were available for the 65/66 Mustangs. This first picture is of a set that was more commonly used on the 65 model cars, although, they were still listed in the 66 accessory literature. These would set you back the extravagent sum of $7.95 for the front mats and $4.96 for the rear. It's identical in every respect to the regular floor mats that are seen all the time in Mustangs now, except for there is no embossed horse on them. These are quite rare now.

This second picture is of a set of floor mats that were available over the counter from the parts department of your local Ford dealership.
This last picture is the set of floor mats that the car would have come with from the factory. These are reproduced and are readily available from any vendor of vintage Mustang parts.

Happy birthday

I just noticed that it was one year ago today that I started this blog. Woooohoooo!! Happy birthday, blog.

Mustang back up lights 1965 and 1966

Here's how that system is supposed to work.

This is the system for a car with an automatic transmission. A black wire with a red stripe comes out of the fuse box, goes out through the firewall, then dives down to the transmission. On the side of the transmission, where the shift linkage is attached, is the neutral safety switch. This switch does two things. It prevents the car from starting when it's not in Park or Neutral, and, it sends power to the reverse lights when the shifter is in the Reverse position. The black wire with the red stripe goes into the neutral safety switch and comes back out of the switch, goes back through the firewall, and the goes to the back of the car with the tail light feed harness, which runs from under the dash, then underneath the driver's side door sill plate, and back into the trunk area.
A manual transmission car has that black wire with the red stripe coming out of the fuse box, and then running underneath the carpet and down through a hole in the floor right behind the shifter, where it goes into a reverse light switch which is positioned in such a way that, when the shifter is in the reverse position, the shifter arm pushes the button on the switch. The black wire with the red stripe then comes back up through the floor, back out from under the carpet, and then joins up with the tail light feed, and goes to the trunk area, just like on an automatic car.
The most common problems with this system are either that the bulbs are burned out, or the ground wire from the reverse light housings have been disconnected or cut, or just got all corroded and funky-looking, or, on an automatic car, the neutral safety switch has gone stupid on you. On a manual tranny car, the same things could happen with the bulbs or the ground, it's just the reverse light switch that goes stupid instead of the neatral safety switch, since it doesn't have a neutral safety switch. If the lights stay on all of the time when the key is in the 'On' position, that is almost certainly a defective switch.

1965 and 1966 Mustang headlight switch replacement

To replace the headlight switch, you have to first remove the instrument bezel. This is not a big deal at all, and I've given the very simple, step-by-step instructions in a piece called, that's right, instrument cluster removal.

Shown below is a picture of the headlight switch connector. Just unplug that from the old switch, as shown in the next picture. There isn't any secret clip that you have to undo or anything, it just unplugs. Sometimes it will be kind of tight and try to fight you a little bit, but, it will turn loose.

Next, pull the switch knob out, as if turning on the headlights.

There is a release button for the knob shaft on the switch, as indicated by the arrows. You can't see it with the switch installed in the car, but you can easily reach it, if you know where it is. This is where it is. You just push that button all the way in and, while holding it in, pull the knob shaft out of the switch.

Next, take a flat bladed screwdriver and unscrew the little bezel thingy from out of the switch.

Then the switch can be removed from the car. Place the new switch in the car, and re-install the little bezel thingy, insert the knob shaft into the new switch, while holding the release button down, and this is what you end up with. A brand new headlight switch installed in your car. When installing the knob shaft, be aware of the fact the shaft is triangular in shape, as is the hole that it goes into. Twist it around to get the shaft lined up correctly with the hole when re-installing the knob shaft. Don't use excessive force, because there are some things inside the switch that you can break. It takes a little force to get it in, but, don't start really leaning on it, or pounding it in with a hammer or something. It is a very simple job that you can easily do yourself successfully.