Originally Posted by THE67MIGHTYMOUSE

Here is my riddle someone can solve. 1965 F-100 4x4, 300ci. Vin # indicates a 300. I pulled the engine for my truck and am in the process of a re-build. Block: C5AE. Head: C5AE. To my pleasant surprise, the head was the smaller closed cumbustion chamber of the 240.(found this out after i went through the trouble of sourcing and re-building a different 240 head, C8AE from a 71 f-100) The cranking assembly was all original save for one piston which was replaced early in its life. Stroke: 3.98. (300ci). Could this setup come from the factory, or did someone make a hybrid using a 240 block and head with a 300 cranking assembly? Thank you to the OP for all the info with the two heads, it has been very helpful.

Originally Posted by THE67MIGHTYMOUSE

Here is my riddle someone can solve. 1965 F-100 4x4, 300ci. Vin # indicates a 300. I pulled the engine for my truck and am in the process of a re-build. Block: C5AE. Head: C5AE. To my pleasant surprise, the head was the smaller closed cumbustion chamber of the 240.(found this out after i went through the trouble of sourcing and re-building a different 240 head, C8AE from a 71 f-100) The cranking assembly was all original save for one piston which was replaced early in its life. Stroke: 3.98. (300ci). Could this setup come from the factory, or did someone make a hybrid using a 240 block and head with a 300 cranking assembly? Thank you to the OP for all the info with the two heads, it has been very helpful.

Originally Posted by trozei

C9 is definitely a date code. It means the part was made in 1969. There was no 9AB used on these heads. It would only be C9. Look at the picture of the 240 head at the top. It's a D2AE, or a 240 head from 1972.

Originally Posted by trozei

I am making this thread to assist those who, like me, are or at least were at some point trying to find and identify a 240 or 300 head for whatever reason. In my case, I wanted a 240 head to install on a 300 block for the higher compression.

Hopefully, when Googled, this thread will show up for people. I found it harder than necessary to find a conclusive answer on the differences between the two. I know the information is out there, but it is scattered all over the place. I'd like to bring it all here in one spot to make it easier for anyone trying to learn.

There isn't much in terms of physical differentiation between the two. Here is a collection of what little differences there are.

All information is for North American vehicles.

If an error is spotted or further information is revealed, please let me know and I will add it to the list. I want to make this as easy as possible for anyone researching. I don't want them to be scrolling through pages of this thread to get their information.

Casting numbers.

The casting number can be found at the front of the head, on the bottom, underneath the thermostat, offset toward the driver's side. Like any Ford part, it will start with a letter and then a number.

The letter represents the decade and the number represents the specific year.

Example: C9

B = 1950
C = 1960
D = 1970
E = 1980
F = 1990

Adding the number, we can conclude that a C9 casting was from 1969.

It can be noted that Ford used this date coding system on pretty well every part they made.

After the date stamp, the next two letters are important. It will either be AE or TE.

Example: C9AE

AE = Automotive Engine
TE = Truck Engine

Ford was notorious for not being consistent with their casting numbers, so I can give no definitive answer. I can only say what things should be. If the head has AE, it is highly likely to be a 240. If the head has TE, it should be a 300.

Any proceeding numbers after the first four are irrelevant.

Availability.

The 240 was used in full size cars from 1965 to 1972, and up to 1974 for fleet vehicles. In trucks and vans, it was used from 1963 to 1974.

The 300 was used in F-series trucks and E-series vans from 1965 to 1996, but in 1987 the 300 was converted to fuel injection, which used a different head.

Valvetrain.

Valves, seals, springs, retainers, rockers, and anything else related to the valvetrain is all interchangeable.

Physical characteristics.

The spark plugs are on the driver's side and the intake and exhaust are on the passenger side.

The head dimensions (LxWxH) are 29 1/8" x 6 3/16" x 3 3/4". The height measurement does not include the rocker pedestals.

Block Differences.

If the head is still on the engine, it is honestly impossible to know for absolute certainty whether or not the head is a 240 or 300 head. All these clues can lead you to believe that it is one or the other, but thanks to Ford's lack of proper casting identification, it is impossible to know for sure.

For further evidence, however, we can look at the block. Its casting number will also be an AE or TE. This casting number is located on the passenger side, down low near the oil pan, and rearward by the starter. Again, AE likely means 240 and TE should be a 300, but Ford often used whatever blocks they had on hand on engines where the stroke was the only difference, such as their "big block six".

So, to know for sure what displacement the block is, we can pull a spark plug, stick a piece of wire down in the cylinder, and measure the stroke by rotating the engine.

The 240's stroke is 3.18" and the 300's is 3.98".

Combustion chamber.

A 300's combustion chamber measures 76cc and the 240's measures 68cc.

The combustion chamber is the biggest difference between the two. Excluding the casting number, it is the only difference. If you have the head on the engine, you can only be hopeful that you have the head you want. If you have the head off the engine, you can instantly know what head you have.

The 300 chamber looks like a D, and the 240 chamber looks like a kidney bean.

Note the difference?

300:



240:

Originally Posted by The Frenchtown Flyer

The 240 head will physically bolt up to the EFI block, with minor exception, but the combustion chamber does not have the proper burn rate characteristics, so doing so would leave you with an engine that doesn't get enough spark advance. That, plus there are two less bolt bosses for the exhaust manifolds. I suggest you stay with an EFI head for a rebuild.

Originally Posted by fordman75

That's a late 70's early 80's 300 block. It could have 240 internals. You won't know without measuring the stroke or tearing down and inspecting rotating assembly casting #'s.

The head is a 240 head.

No clue on the transmission. Is it a manual or a automatic? If it's a 3spd manual it should just be a the Econoline version of the 3.03 3spd. If it's a automatic I believe it should be a C4.