65 F100 - 240 or 300?

[jfm]

I am probably going to buy a 65 F100 in the next few days. It has an inline six that I thought was a 300 for the reason stated below.

The Wikipedia page says that the 300 has separate intake and exhaust manifolds while those for the 240 are made together:

Unlike the Falcon engine, it (the 300) featured separate intake and exhaust manifolds, which could be easily replaced with aftermarket manifolds offering the promise of even more power, through the installation of larger carburetors and a higher flowing exhaust system.

On the other hand, on the fordtruk.com inline six page, it says that the 240 and 300 are identical on the outside. So, which is correct? Is the Wikipedia statement not true, and, if not, then is there anyway to tell one from the other from the outside?

Thanks.

[don morris II]

the 240 is not a falcon engine i believe 170 200 250 have the intake cast with the head. the 240 300 are truck engines also found in a few full size cars and are separate if hope this helps

[roadstarman58]

It's more than likely a 240. That was the standard engine starting that year and into the 70's. 300's were used on F250's and up back then and didn't become the standard engine in 1/2 tons until lthe mid 70's or s0. They are interchangeable. The Falcon 250 will bolt up to the bellhousing as well since they all have the small block V8 bellhousing bolt pattern.

[Brian Taylor]

I would think it is the 240 if it is the original engine. But the 300 was often the replacement if has been replaced. My truck was an original 240 but had a 1983 300 in it when I bought it. 40 years things change.

[jfm]

Then is there no way to tell from the outside?

[Gatkpartz6179]

get the casting numbers on blockside, that may tell ya.. on earlier 6 223/262...223 was c_ae...262 was c_te....

[jfm]

Okay, it turned out to be a 66 instead of a 65. The fourth digit in the VIN is a "B" which should indicate that it is a 300. Also has three grooves on the crank pulley.

[cdherman]

get the casting numbers on blockside, that may tell ya.. on earlier 6 223/262...223 was c_ae...262 was c_te....

240 and 300 have the same block, same casting. So that will not tell you jack.

Disconnect battery. Loosen all plugs and remove #1. Use a wrench or ratchet to turn the engine over with a dowel or brass rod on top of the piston. 3.96" = 300 3.25" = 240

Best way to tell.

Heads are also different --- if you are really good you can get the casting number off of the head with a dental mirror. Its underneath side of the head, right behind the thermostat housing. The head hangs over a bit there. #1 approach is easier.

Finally, though not 100% perhaps -- if the water temp sensor is on the passenger side of the block, I think that means its a 300. The early 240 heads had the temp sensor on the rear of the head (right up against the firewall)

The 1 ring versus 3 ring harmonic damper thing is unreliable. Some 240 had 3 and some 300 had 1 ring. Go figure....

[realisticretiredone]

I thought I read somewhere about counting the freeze plugs on the side of block, 240 had 3 and 300 had 5 I think.

[cdherman]

I thought I read somewhere about counting the freeze plugs on the side of block, 240 had 3 and 300 had 5 I think.

While it may be true that some early bocks might have been 3 and later blocks might have been 5, fundamentally, in a given year 240/300 production, they used exactly the same block.

If you have an EFI block, it certainly is a 300. The EFI block will not have the fuel pump boss machined. Aside from that, just looking at the block will not tell you definitively.

[BigMike]

get the casting numbers on blockside, that may tell ya.. on earlier 6 223/262...223 was c_ae...262 was c_te....

240 and 300 have the same block, same casting. So that will not tell you jack.

Disconnect battery. Loosen all plugs and remove #1. Use a wrench or ratchet to turn the engine over with a dowel or brass rod on top of the piston. 3.96" = 300 3.25" = 240

Be sure to use a dowel longer than 4"