Anyway, back to the 240 topic. Im a fan as they can rev a little higher but be aware, you CAN pull the rocker arm studs, which is not nice, but easily fixed with a "farmer's fix" I have heard of people adding to these like they add to 300's, they will just always be the little brother.

 

All right back to the 240 I6 the baby 300. It has a ton of low end torque and was an option for the light duty pick-ups in the late sixties.

I have a split manifold and dual exhaust with some old glass packs. The truck sounds great.

I have had a ton and a half of gravel inthe back of the truck an the 240 pulled it up and down hills without complaint.

I had carb problems for awhile and eventually repalce it with a rebuilt and found the original oil bath air cleaner to go with it.

Sorry about previously drifting off subject. I would liek to here more feedback about the 240.

 

Is your "split manifold" the original manifold with an extra flange welded/clamped on, or something else. I am have a pair of late 300 EFI exhaust manifolds that I a thinking of using. About half people on these forums seem to like using a factory "Y" pipe into a single muffler and the other half go for a true dual system. Is your sound on the harsh side?

 

I've owned two of the 240s. The first was in a 73 short bed with a 3 speed. Great motor & it got good mpg. I didn't tow anything with it bu it hauled mytruck load of tools great.My other one was a 68 long bed with a 3 speed. It was stronger due to a lower geared rear & it didn't get as much mpg. I swapped a 300 in it when the 240 died. I liked my two 240s.

 

I was thinking about adding the late 300 efi exhaust manifolds, and maybe true duals, but i heard the sound really is not that good. As for mileage, my truck gets about 20mpg highway or in the city, with a rebuilt carb and the original oil bath oil cleaner.

 

Archie:

My split manifold is truly split. I bought the truck a couple of years ago from the son of the original owner. The original owner had the split manifolds put on in 1969. Cyls 1,2,3 exit on the passenger side of the truck and cyls 4,5,6 exit the drivers side. Two exhaust manifolds two flanges two head pipes etc. I love the sound with the burned out glass packs.

Now why do I love my 240.

The old truck has been feeling grumpy the past couple of days. A little miss under load, a little hard to start, start and die in the mornings and this morning died at a stop light.

Started it up after work ran fine, drove home pulled into the garage. Pulled plugs nothing spectacular, all burning cinimon color, checked gap and reinstalled. started truck, checked dwell 37 degrees, timing 6btc, idle 550 rpm, quarter turn on idle jet brought rpms up to 575. Popped distributer cap pulled condenser check with ohm meter had about 10 k ohms resistance. Replaced condeser. Drank beer, moved truck to it parking place. My wife parks the Vette in the garage, the old truck has to stay at the side of the house. Pulled truck back into garage to wash windshield. Drank Beer, listened to Toby Kieth CD. Moved truck to parking place, truck runs fine.

Now why do I love the 240...... Let me count the ways.

1. I don't carry the phone number for the dealer in my wallet.

2. I don't have to remember my warranty number....I am the warranty

3. I don't have to have a scanner and a laptop to find diagnose what is wrong with the truck.

4, The truck ALWAYS starts and runs even if it is feeling grumpy, it gets me to and from wherever I want to go.

5. If it is raining and the streets are flooded the truck doesn't care if water is running in the doors the 240 just keeps chugging along oblivious to adverse conditions

6. Oh my God i had to spend a couple of bucks on a condenser, better than $50 dollars on a CPS.

7. The work I did today did not require one metric tool.

8.The engine tells ME when it isn't feeling good not the computer which will try and compensae for a minor problem.

9. What sensors the 240 doesn't have any.

10 Had to repalce the distributer after I bought the truck. Cost 90 dollars

11. Had to replace the carburator Cost anoth 90 dollars

12. Never have to buy and air filter......just change the oil

I spent about 45 minutes this afternoon working on the truck spent a couple of dollars drank a couple of beers listend to some good music. The 240 runs great and I still have money for more beer. What is not to love.

 

Pure poetry . . .

(Let me get this right: stock log manifold, added flange at front . . . is there a block between the ends of the log? Heat riser to carb?)(OR is this an aftermarket pair of manifolds, ... headers?)

 

OK Now ya got my curiosity up..... I had to go look.

Take a stock cast iron exhaust manifold and cut it between #3 and #4. Cut out about a quarter inch from each piece and weld the ends up. Cut a hole in the short piece that attaches to #'s 1, 2 & 3 and weld a cast iron flange from a donor exhaust manifold.

The modification to the front cylinders looks like they took a stock cast iron manifold and cut it just below the heat riser block and grafted the piece into the short manifold. The modified manifold exits at the bottom of the manifold between #'s 2 and 3.

I hope this helps. You have probably seen it before. Don't know if it helps performance or not but is sounds cool.

 

Dan-J, thats sounds like a cool idea, and a really different look. Do you have any pictures of this?

 

Just what I thought. The front & rear halves of these I6 engines are sort of like two separate engines if you study the firing order. Each half has three cylinders that fire at 120-degree spacings. (This is why your manifold works and also why the 300EFI units have two separate 3-into-1 manifolds for the two halves.) I have a hankering to build a custom intake manifold that uses two one-barrel carbs - one for each half of the engine. I am considering using the lower half of an EFI intake manifold and then fabricating two little "logs" to tie each of the carbs to three of the ports.

The main thing I am concerned about is that unlike a 4-cyl or the halves of a V8 (which are 90-degree intervals AND have strokes that are also 90-degrees), the half-sixes have a 120-degree interval BUT a 90-degree stroke. The 90-90 situation means the impulses in both intake & exhaust follow one right after the other. With the 120-90 (sixes), there is a gap between impulses of 30 degrees. In the exhaust, this leads the the "harsh" sound that sixes with a split exhaust are known for.

More thinking necessary regarding what happens in the intake . . .

 

Hey Twin 66,

I just looked at your profile and before we get to the manifold I gotta ask. How the heck do you live in the frigid cold weather in Alberta. I live in Tucson AZ, USA and it got down to 19F , that is 19+, not minus and I thought I was gonna die. A couple of days later they anounced a big global warming thing. I wanted to move to the global warming area. I just can't seem to function below 70 degrees F. I guess I am just a desert rat or maybe a lizard. It was 85 degrees today and I am loving it.

No back to the manifold. I will try and get some pics posted. Our digital camera is broken but both my teenagers have cameras on their cell phones. Since I pay the cell phone bills I think I can get some pics posted.

The first split manifold I saw was in the early sixties on a 51 Chevy with a 216. The modification was popular in the sixties before aftermarket companies existed and most work was done in the garage.

Archie:

Sounds split intake would work. Gotta a couple of questions though.

1 Why 2, I barrels instead of 2 two barrels. I know it is an air flow thing and I would have to look at the CFM requirements and go from there. Just off the top of my head (which is like the head of a pin) it seems to me that if you open the intake and exhaust the engine will breath better and even with the stock cam should be able to handle more CFM.

2. Do you plan on heating the base of the carbs? If so how?

 

Dan,

This is rarely an answer you will hear from me, but sometimes . . .

I have two "cute" Holley one-barrels from the two 223's I have had in my '61 F-100. (Taken together, the 223's had 12 bad rod bearings, hence the 240 conversion.)

I have had some good-running 223's ('56 Ford sedan & '57 Ford panel) so I have a "warm spot" for these carbs. Did you ever see the variation of these carbs that has a transparent float bowl so you can SEE that you are getting gas to the carb & that the float level is correct?

I figure that if a single Holley one-barrel carb can feed a 223, two should be plenty for a 300. Any more carb area and I think some sort of progressive system would be required. (I do suppose that I could use a pair of progressive 2-barrel carbs, but they wouldn't be appropriate for the truck. Anyway, if the ones's don't do it, then I can go to the two's.

I had a friend with a 312 Y-block that ran a 3-2-barrel carb setup that had a rigid linkage. It was OK, but I GUARANTEE that if you were in any gear and punched it, there were two possible outcomes:

3,000 rpm & below, there would be a loud "woosh" and the engine would act exactly as if you had just turned the key off.

3,001 rpm & above, it would literally take off like the proverbial "bat out of hell", plastering you back in the seat. (He did go back to a 4-barrel.)

The carb-heating is an issue that is still bouncing around in my mind. IF I ever do this mod, it will be on a 300 that might be in my '68 F-350 which is primarily used for hauling/towing. (It will also have the EFI exhaust manifolds.) From '94 through '01, I made a DOZEN cross-country trips hauling 5,000 pounds (NET) per trip. The 390 engine that stood up to all this had no thermostat and the heat risers were totally blocked off. This engine needed a long warm-up, but it did fine. In general, I believe in carb heat & thermostats. As I said, I'm still thinking . . .

Anyway, I have the carbs and it gives me something to think about. This is not one of my most serious projects. I do appreciate your feedback.

 

Hey Guys, Haven't posted here in awhile but this thread caught my eye.....I drove a 72 F100 for years. 240, 3 on the tree. I converted it to a three-on-the floor, though. Had a lot of fun in that truck, a great little engine that literally would not die. I re-did the body on the pickup, repainted it, put nice wheels on it, and wanted to put a 351 in it REAL BAD! My parents were financing most of the restoration, as I was a junior in High School, and poor as dirt. They said that there was no way they would help me buy a 351 when the truck looked good, and had a perfectly good engine in it. Being dumb high schoolers, my best friend and I decided to remedy the whole "perfect engine" thing. We drove the truck about 5 miles down to the river in first and second gear, holding the pedal to the floor, and keeping the engine revved as high as it would rev, about 5500 rpm. That didn't do it, so when we got down to the river, I got out and drained all the oil out of it, and we beat the **** out of it all the way home, just over 5 miles-without a drop of oil in it. By the time we got home, it was overheating bad, and wouldn't rev much past 2500 rpm, it was starting to seize. Wasn't knocking though, much to my dismay. Shut it off, and tried to re-start it, she was locked up. Mission accomplished, or so we thought. I poured a gallon of used motor oil back in the crankcase so my dad wouldn't know what we'd done. When my dad came home about 2 hours later, I told him I thought the engine was shot. we went out, and he jumped in it, turned the key, and it started right back up!!! He was all like "what the hell are you talking about"? Drove it around the block, and said it seemed fine to him. I was baffled, and to this day I still can't figure out how a seized motor can un-seize itself and run fine. The truck was rolled about 3 months after that, pretty well destroyed. I sold it to a farmer who put a flatbed on it, and 12 years later-the truck still runs. He doesent use it much, just uses it to tug hay and move trailers around his farm. But I'm convinced that those little 240's are some pretty tough engines.

 

" . . . to this day I still can't figure out how a seized motor can un-seize itself . . . "

My guess: When running hot, the aluminum pistons expanded enough to sieze in the bores. (Aluminum expands much more than the cast-iron block.) When they cooled down, the clearances were again near normal. (I'll bet the bottom end of the engine was not as pretty as before.)

Great story, but I hope you do not test your current Fords this way.

 

LOL, well, up here in Alberta we are basically used to it. Either that or our outer skin is frozen solid But I am just the opposite, as soon as it gets over 86F or so, I cant stand it! (yes, in the summer it does hit that every now and then)



Anyway, back to the 240, mine was actually rolled about 20 some years ago by my second cousin into the ditch on a wet gravel road. Well, they rolled it over, topped off the oil and drove it home. Of course, it pushed in one part of the roof, and a jack-all was used to straighten it back out for the new window. It still runs fine ever since last summer when I hauled it home, cleaned the carb, changed the oil and replaced the fuel tank from another 66 I have.