I have an old 68 Ford f-250 runnin a 240 L6. What are the power differences b/w the 240 and 300. And what engine mods are out there to beef up an inline six, specifically a 240.

 

Answer to both: Not much.

See the sticky above re power for the 300. Head described as a "cork".

Turbo and other high dollar mods will get respectable power.

In a truck like yours with lots of room and no smog, you can go header and 2v or 4v manifold, fool with the ignition and if you want to go more, then balance and blueprint the motor, shave the deck and head, and get a more aggressive cam. This will move you into the 200-250 horse area, methinks.
Read on, as this is one of the top 10 questions of life.

 

The 240 and 300 are amazingly similar in terms of parts, yet they behave a lot differently. The 240 can rev a lot higher due to its much shorter stroke, and of course has less torque at lower RPM. With the right tranny and gearing, they can perform similarly, but at vastly differnent RPM. In some ways, the 240 is more similar to todays more modern high reving engines.

The 240 does retain, and perhaps exceed, the 300 in a one characteristic -- it is very tough, capable of lots of miles and abuse. For a truck, it really was a poor choice in an era of cheap gas, as its marginal better economy was no decent trade for the better drivability of a 300. For a car, it is a poor engine as well, as it is just too heavy. It cost the same as a 300 to manufacture, so when more people wanted 300s instead of 240, Ford saw the light and phased the 240 out.

I think that the general consensus is that the available mods, including different intake and exhaust headers, as well as different carbs, are worth the effort. Port and polish done right will add performance too. It has a lot more available parts that some engines that began their design life in the early 60's, so in that sense, its a sucess.

If you have a 240 in a vehicle that you intend to drive much with todays ever increasing gas costs, you may do well to hold onto it. It will get better gas mileage, according to what I have read. Mine is at about 15 mph, with a stock intake and exhaust and Carter YF. And that's not even tuned very well. I have read of people with f100 getting 18+ mpg, honest mileage, with a 240. Anyone who says they get that with much else in a 5000 lb truck is mostly blowing hot air.

 

There was a 10-20hp difference in the 240-300 depending on year but the 300 put out 283lb.ft. compared to the 240's 234 lb.ft. of torque and both the horsepower and torque were a couple hundred rpm lower with the 300.

 

Alright now let's get specific, what parts (brand names please) do I need to put on my 240 to get it to run stronger.

 

Used or new 1987-96 EFI cast exhaust split manifolds -- Junk yard, about $60

Custom split dual exhaust with crossover pipe cost is variable.

Offenhauser DP manifold $199 from JEGS etc, a little less used on eBay

Holley 390cfm 4 bbl carb -- about $300, maybe a little less.


"RV" Cam, brand I cannot comment on. I would be careful with the cam on a 240, as most of the cam recomendations are based on 300 performance. Might want to discuss with the cam maker over phone first, or just leave off the cam for now.

With the above config, you will have no heat to the intake manifold. Depending on your driving conditions, you may someday expereince carb icing. If that occurs, you can put in a heated carb plate, fashion a block off plate to heat the intake, or rig a "stove" to get hot air from the headers up into the air intake. All work, all are unnecessary for many folks, so I would just wait and see.

 

Sweet, thanks for the posts... will let you know how it turns out.

 

I thought some folks gained on the 300 by using the head off a 240, for its smaller combustion chambers--IIRC

 

I heard the same that the 240 head used on a 300 will raise compression a little.

 

Wouldn't headers be better than a split manifold?

 

Headers don't flow a whole lot better than the efi manifolds, but most would give a slight improvement, so slight it may not even mean a power gain of more than 1hp.

 

Yes the 240 head on a 300 will raise compression as the combustion chamber in the 240 is a little smaller. The other approach is to shave the deck. Since the 240 has a touch higher compression from the get go, I don't know that such a mod would gain you much in a 240, other than the need to run expensive racing fuels to prevent pre-igntion.

The cast EFI manifolds flow so well that they are almost as good as headers. And they won't rust away. And they are cheap. For the utmost in performance, of course you will be better with headers. But how much is debated.