Would’ve posted this in the towing section, but I feel like this is less about towing and more about beefing up our truck.

So we bought a vintage camper trailer, and went to go pick it up last weekend, about 800 miles each way. The camper itself weighs around 3k lbs.

Our truck is a 1966 F100, original 240, C4 trans, 3.50 gears. Running gear is all stock and all original as far as I know. This truck is rated as 5k lbs towing capacity. I ran a trailer brake controller and installed a class 3 Draw Tite hitch, and also used a weight distribution hitch from Curt.

So now that you have the background, here’s how the trip home went…

Most of the driving was up huge hills through West Virginia and western PA. The truck could barely make it up the hills… I’m talking maxed out at 25 mph with the gas pedal floored. A little scary on highways when people are flying around you going 80 mph, I was scared we were going to get rear ended by someone not paying attention. But yeah, on perfectly flat ground she’ll pull the trailer at 60 mph no problem, although it takes an hour to get up to speed, lol. but on any kind of a grade… forget it. The most it will do is 25 mph. I had to disconnect the kickdown so it would stay in 3rd gear, otherwise it kept bouncing back and forth between 2nd and 3rd the entire time trying to make it up the hills.

We eventually did make it home. No overheating, the temp gauge normally sits at around 1/4 and at most on some of the longest hills it got up to about half, but never any higher. I did check all the fluids constantly, and noticed on the ride home the oil had some creamy whiteness to it, which it never did before and hasn’t at all since, so that’s kinda weird.

Anyway- lessons learned are… definitely going to install a trans cooler and contemplate power disc brake upgrade, although the trailer brakes did a great job, so believe it or not braking down some of those steep hills with the original drums wasn’t all that bad.

But why was she straining so hard to get up those hills? I keep hearing about how these L6’s are built for torque and can tow almost anything. What’s the weak link here? The motor just being tired and old? The trans? Rear gearing? What should I look at first?

 

An original 240 when brand new had 129 HP. A new Ford Pinto had 95 HP. With a worn 240 you might be closer to the new Pinto. The 240s also came with the Load-O-Matic distributor - and matching carburetor - which only had vacuum advance and only worked well when everything else is working well. The 3.50 gears aren't helping much for up hills and the C4 automatic isn't as direct as a manual transmission, so you have some extra losses there as well. One good thing about it is there are lots of ways to improve upon it for better towing.

Ford 300 (same exterior dimensions as the 240 and you could upgrade your 240 to a 300) with dual advance and EFI exhaust or headers and Offy dual port intake with a 4 barrel carburetor would make a big difference in most cases.

 

Truck and trailer you're over 7000lbs. I don't believe a 240 with a whopping 150 HP and 234 ft. lbs. of torque at sea level is ever going to do much better. If you are having to drive it foot on the floor to get up every hill you are just going to kill your engine or transmission.

 

Chad shop manual says 150 hp and door tag 129 why the difference. You are correct though he needs more cubic inches.

 

150 Gross - 129 Net

 

Altitude in those hills rob a non turbo older engine of power, Back in 1980s made a trip to florida with a chev caprice wagon with a 305 in it . Could not believe how much power it lost in hills going south from Erie Pa through Virginias.

 

Forgot to mention that it has a new GM style HEI distributor and a Carter YF 1 bbl carb. That’s the only thing under the hood that’s not stock.

So it sounds like the general consensus is that the 240 isn’t up to the task. Like I said, the motor is tired and old… I’ve never tested the compression, but it leaks like crazy and smokes a little, and does use a little oil.

So would the first logical step be to look for a good running 300? Any parameters to keep in mind on my search? i.e: specific year range? Van or truck? Etc

If funds were slightly limited, what would make the most sense- buying a brand new reman long block 300 and leaving it stock, or a buying a used 300 and adding mods like efi exhaust manifold, 4 bbl manifold and carb?

 

Try the I6 forum. Ford Inline Six, 200, 250, 4.9L / 300 - Ford Truck Enthusiasts Forums (ford-trucks.com)

 

Change the gears in the diff as a start.

 

Wind the biggest factor.
only solution i can think of is drop that trailer off at my place & let me worry about towing it…

tall trailer, low power & poor brakes not a combo i would want to do in the hills.

Not going to be a cheap solution unless you re-power with major upgrades.

 

These I6's do/did make good torque...for their size.

Interesting question for those on a budget...buy reman or buy used and add performance parts.. My preferred strategy, based on trial, error, and money misspent is to learn about your engine of choice. As was mentioned, hop on the I6 forum here but also look for other dedicated I6 forums. I'm sure you'll find some nuts who really know the I6's well. Then find a good builder. That way you get it done right the first time and you can get what you want. It's not the cheapest at first but I believe it saves money in the long run...if the long run is the plan.

I6's aren't going to tow like the big V8's, but you should be able to handle your camper with a well built I6. Nice thing about these engines is they run a freakish long time.

 

Thanks for all the comments! Lots to consider here, but I think I’ll start by searching for a 300.

The trans leaks from the shifter seal (I think the hole is worn out of round), but it seems to do okay and shifts alright for now, so I think I will try to address the motor first. I’ll hop on the l6 forum and poke around there a bit.

Im the meantime if anyone has a 300 laying around or has any leads on one, let me know! Im not finding anything on Craigslist. I’m in Delaware but willing to drive a few hundred miles if needed. Thanks!

 

Creamy white oil, no bueno. You must have had some coolant in it, or moisture of some kind. May have evaporated/cooked out since then. The 240 is wheezing and not long for this world me thinks.

 

Would a 390 FE be a better option for you if you want to stay with a vintage Ford engine?. Others will weigh in here about fitting it to the transmission and motor mount issues...and if its worth the effort and what is required.

 

The inline 6 has a higher "cool" factor these days because they are unusual. Everyone and their cousin yanks 'em out to put V8s in. My own truck has the 300. It has the Holley single barrel Sniper EFI and an HEI distributor and a T5 five speed trans. I don't think I'd wanna tow more than 3000lbs with it. But y'know, back in the day, it was a common thing to do and you just went slow up the hill. The last older truck I had that I towed with was a '74 C10 Shiverlay with a 383 small block (stroker). It could pull as fast as you wanted up a hill and sucked down the gas doing it.

Lots of engine combos out there that would be up to the task. To convert your 240 to a 300 just means a crank, rod and piston swap. Everything else is the same. In fact a lot of guys use the 240 head because the chambers are smaller and it gives a compression ratio boost. But, building up a 300 is not gonna be cheap. The 4 barrel intake manifolds are well over $600 now. I have not been able to find one used. Maybe a 302 or 351W would be the practical choice to tow with. Especially if you can find a good running used engine/trans. Plus used hard parts are fairly easy to find.

On a side note, if my own 300 was not rebuildable, I was gonna swap a 2JZ toyota into it. With a turbo, they make a BUNCH of power!

You have to weigh your needs/cost/mechanical ability to chart yourself a course of action. And while it may tick off the ford purists, sticking with a Ford powertrain may not be the most inexpensive/efficient option to consider .