Hello everybody, my F100 project has about stalled(OK, it has ). I`m thinking a new direction is in order, something with some bigger tires....

I currently have no engine(truck is a `66). A friend has a running 240 I can get for next to nothing, out of a `69. My truck is setup for a 240 in it. I am strongly considering making the old girl a 4x4(both trucks are 2wd). I know most any transmission from a 300/302 will bolt up to an old 240, but I get a little fuzzy on what to do with the flywheel/clutch/starter.

I want a 4 speed with a granny gear, I think I`ve settled on the NP435. The `69 is a three speed. So I have a good starter and flywheel for it(needs a clutch). Or do I need the starter/clutch/flywheel from whatever junkyard truck I get the transmission from? Or some combination of the above? This got confusing fast for me. I looked around the web, maybe I`m searching the wrong thing. I can handle the axles, transfer case, etc, but I need a spot of help with this(will be asking the 4x4 forum guys opinions on gearing).

Thanks guys,

 

Correct, the 240 uses the same bell housing/bolt pattern as the 300/302/351 so all those transmissions are interchangeable. On that note, the NP435 is a great transmission.

Also, I'd encourage you to share up your gearing ideas here, since the 240/300 has different RPM ranges and power bands than a lot of the 4x4 guys are used to.

As for the flywheel and starter, what 3 speed did the '69 truck have in it? That may dictate if it's compatible. If not, I imagine just track down a flywheel/starter for any year that used an NP435 stock.

 

I really couldn`t tell you, I never looked into the three speeds. I didn`t even know there was more than one available

So, the 240 is internally balanced then? I read about this before, but it`s awfully fuzzy now....

From my gearing thread:

 

Due to the nature of their design, all straight sixes are inherently mechanically balanced.


RPM = (Speed * Transmission Gear Ratio * Final Drive * 336) / Tire Diameter

This formula will let you know what RPMs you'll be at at any given speeds.
What is the max speed you'll be driving the truck at on a regular basis?

One thing to consider is the weight of 35" tires as well. They're going to take more gears to turn them.

If you were to cruise at 65 on the interstate with 35" tires:

RPM = (65 * 1 * 3.54 * 336) / 35
RPM = 2208

That's a pretty nice cruising RPM, but with 35" tires may lack for strength on steeper hills, causing you to lose speed. 4.11s would put you at 2550 RPMs @ 65. Those RPMs will lower your gas mileage some, but you'll gain strength. It depends on where you want to compromise.

My '81 has a 3.00 final with 31" tires. One thing I like about the lower gears with the NP435 is that it keeps my highway RPMs down, but I can start out in granny gear to get the truck moving easily in normal every day driving.

My '84 with 3.55s, the granny gear is so low it never gets used except when I'm moving a boat or something.

 

I looked at work today(two perks of working at autozone: much improved part lookup capability, and 20% off ), and it looks like the flywheels for all manuals were the same from at least `66 up to `77. Then from `78 to `92(where I stopped looking, figured I wouldn`t be getting a newer trans than this), was a different part, but the same throughout those years. So I`ve got a pretty good chance of finding one.


That`s what I was thinking, but I didn`t want to spout off and look like an idiot


I`m a bit of a number junkie myself when it comes to these things. I`ve been playing with this calculator. It`s kinda nice, lets you see all the gears and hi/lo range.

It`s a miracle around here if I drive a leaf sprung, lifted 4x4 on 35`s over 60mph for any length of time. That`s where I cruise on the highway. It would mostly see backroads, a 2 mile jog on the highway on the way to work, and the occasional load or trailer. Oh, and any snow I can find(love driving in the snow). Also, I`m not opposed to downshifting on hills, and not the kind of person who absolutely has to hold speed up a steep hill. If I needed that, I would have to just spend the money to get a zf5. Going for budget here, that way I can drive it and break stuff sooner

I am planning on 12.50" wide tires, so they won`t be as heavy as those 15.50" swampers everyone around here likes to run on the street. They`ll be on steel wheels though.

It looks like 3.54`s will be ok, maybe 3.73`s as a compromise though. I know with a low first, and a good t-case low range(2.69 if I find a 1356 like I want), I don`t need 4.10`s. I just don`t know of the availability of 3.73`s. I would prefer to find some axles already geared what I want to lower cost. I`m not married to the idea of a 9in either. I could go 8.8 if I can find one with the right ratio.(or maybe even 3/4 ton axles if I get a good enough deal, but I don`t want to run 16" or bigger wheels)

Are both your trucks 2wd?

I had an`88 dodge fullsize and my `78 f250 that both had 35`s on them. They both had 4.10s too. The ram was nice to drive(had a 318/auto), and the 250 was a downright beast(400/c6). It would spin the 35`s on pavement

I think with the lower first, and less drivetrain loss of the 435, I can go a little higher on gears. A 240 won`t be a monster like that 400 was, but it should still be plenty driveable and return decent mileage.

Overall I want this truck to be a decent compromise of street and trail, hence the mid-size tires, half ton axles, planned low lift, and trying to find an axle ratio that won`t stall constantly off road, but won`t top my speed out at 45mph on road.

Holy long post Batman!!!

 

Plus, they're a dime a dozen, so they should be in about any junk yard you look in, if you don't want to go new.

Those are nice. I ended up programming my own so I could see it all in real time. But yeah, the numbers and calculations behind gear ratios/tire sizes, etc. can be really interesting.

Hrm... If that's the case, 4.11s might do you really well. If 60 is your top speed, that'd put you at around 2300 RPMs, which isn't bad at all. (75 would be at 3000 RPMs, which is totally doable) With the 240, you won't have the torque of the 300, so you may need the extra RPMs to keep your large tires moving. But, the narrower 12.5" tires will definitely help keep the rolling mass, and the friction down. But, 3.73s would be a great compromise. May just come down to what you find first.

Agreed, though, finding axles with the gears already in them can save a lot of money down the road.

Personally, I'm a fan of the 9".


I have an '81 and an '84 Bronco, so both are 4WD. The '84 has 3.55s with 31" tires and ugh, without an overdrive, I'm at nearly 3000 RPMs at 75mph. That'd be fine if it was my off-roader, but it isn't. It's a cushy, front bench, highway cruiser, so I'd love to get the RPMs down. I usually just drive it at 65 because of that. However, it seems happy at 3000 all day long, so it really just comes down to gas mileage. The power around town is awesome though!

I'll be curious to hear how the 240 does. Most ever I hear of them, they're being swapped out for, or changed into, the 300. It sounds like you'll have a nice truck when it's all done.

 

I`ll probably just get the whole shebang out of whatever junkyard truck has the transmission and t-case I want. If I have to piece meal it all together, I think I`ll just post a CL wanted ad and see if I can`t find one already out.

I`ve been leaning that way myself, the more I think about it. If I put in low gears now, and I`m not happy, I have to find an OD tranny. But, if I put in high gears now, and I`m not happy, I have to re-gear later. I`ll think I`ll be happy with lower gears anyway. I keep going back and forth on this. Like you said, may be whatever I get first.

Ok, I just saw that you only had the rear axle listed in your sig, got a tad confused. So did they not make 2wd Broncos before a certain year?

Me too I just have easy access to one. I figure any tricks that work on the 300 will work on the 240, and I just happen to have some chevy 250 rockers around, and a friend has some EFI manifolds....
I think it will be fairly nice, but hopefully not too nice to hammer off road from time to time. I do plan on tube bumpers front and rear, and full length sliders for the sides. Got to protect my increasingly rare sheet metal

 

I think that'd be the best way to do it. Find a truck in the JY with one, pull it out, and take the shifter, flywheel, Tcase, etc. everything with it.

(The higher and lower terminology refers to the number. 4.11s are higher than 3.50s.)
But, agreed. Regearing is expensive, or you have to track down axles. If you don't like the 4.11s, you can just put in an overdrive, or even a Gear Vendors. The lower gears will require regearing.

I usually forget to mention that because ALL Broncos (aside from a rare few that were sold in Mexico or something) are 4WD. You couldn't get a 2WD Bronco from the factory. I was listing that one was a 9" and the other was an 8.8", since they're automatically Dana 44s in the front unless they've been swapped out.

Should be able too! About the only difference besides combustion chamber size is the crank and connecting rods (and I think flat top pistons), but that should change any of the other upgrades you can do, like cams, exhaust, intake, etc.
Does the 240 have a higher RPM limit than the 300 due to its shorter stroke?

 

Yep. Looks like an early to mid 80`s Bronco or F-series should have the appropriate trans/t-case. Maybe even part of the floor if the trans tunnel unbolts. Could save me a headache when making it fit in the `66. Any idea when ford switched to a hydro clutch?

Really? I`ve always heard that a higher number = a lower gear, and vice versa. Could be wrong though
Gear Vendors would be sweet!

I was in a hurry when I replied, but I never knew that. I used to be big in dodges, and I know their Bronco equivalent(the Ramcharger) could be had in 2wd. Same with the Blazer.

No idea(I was wondering the same though). I have very little 240 specific knowledge right now. I figure I need to worry about how to hang the axles before I play with hopping up the six banger.


And on that note, I was looking at the truck today. It`s currently in a million and a half pieces, which is convenient as the front half of the frame is exposed. Looks like I may be able to pull off a coil sprung SAS easier than a leaf sprung. Much, much more research is required, but I have a good head start on coils. Also, the truck has a 9" under it, not sure how usuable it is(or what ratio it has), but I may save money there.

 

I *think* '83. If not '83, then '84. My '84 is a hydro clutch but I remember hearing '83 was the first year.


My mind is really working overtime to figure out what I was thinking yesterday. (Gave up coffee a little while ago, maybe it still needs it.)
Yeah, geared really low = higher number, geared high = lower number.

Me ->


Yeah, it's kind of a fun little bragging perk of the Bronco. It's the only one that I know of that always, 100%, came 4WD. Well, except for the Jeep Wrangler (at least until 2007).

You need to take pics!

Looking forward to hearing how it does when it's all together.

 

Cool, now to decide which I want....

.....

I know even the Samurai, and the CJ came in two wheel drive as well. And they are some of offroading`s biggest icons.

Working on that. Going to the garage in a few minutes, armed with an actual, real life camera. No crappy phone pics today
I`ll keep you posted on progress. Now, where to start the build thread for a inline powered, 4x4 converted `66 F100

 

Ok, so here`s what I`m working with(real life kinda got in the way of posting for a few days ):













It`s really not in that bad of shape, just needs put back together. Like everyone says on Craigslist "It ran great when parked 600 years ago, just needs an engine/transmission/rear end to run again!"



I do need some new cab mounts though....

 

Haha, wow, that thing is in pieces! You've got quite a project ahead of you, but it looks like a fun one.

Heh, your comment about "running great when parked..." reminded me of this comic:




Granted, yours looks in a lot better shape.

 

Haha..this thread caught my eye..Idk why..but I've been reading on it. I can't say I exactly know what your asking..but I did come across that the bellhousing quill work for a 300/302/351. Which 351? C or w? Cuz in the future waaaaaay down the road..I want to build a Cleveland to put in there..ok..sorry for the thread jack..resume!

 

@AbandonedBronco
Ya, it was mostly whole when I bought it, and supposed to run. You see how that worked out.....

@68Cabby
Should be a windsor engine that has the same bellhousing pattern as the 300/240. The cleveland engine has the 351M/400M bolt pattern(pretty sure anyway).

Do you guys think I should just make this my build thread?