I recently purchased a 1969 F-250, four-speed manual transmission with 106K miles on the 6 cylinder 240 ci engine. Love the truck, seems to have been taken care of but no modifications. It has no problem getting up to 40 mph, but at that point I feel the need to shift into fourth. From there it really struggles to reach 60mph -which appears to be it's top speed on flat road. It easily falls back down to 40-45 mph on a slight incline. I'm wondering a couple of things: First, is this normal for this engine? I've never owned one of these older trucks before. This was originally purchased and used as a farm truck for most of it's life, so maybe there was no need to reach freeway speeds. If it is normal, are there any simple modifications I could make to get a little more power out of this engine? It would be nice to know I could take it on the interstate if necessary. Any advice will be much appreciated.

 

There's a big difference in torque between the 240 and the 300. My '69 F100 (short bed, C-4, 3.50 gears) has and old and tired 240.

Speed does fall off on inclines but, despite the wear on my engine (170K miles), it seems to be happiest at 60-65 MPH.

If I was staying with an inline, I would swap my 240 for a 300.

 

Thanks for that info. I'm sure upgrading the engine would make a huge difference. Hate to swap a great running engine though, unless there's no choice. Should've mentioned that one of the few things the guy I bought it from did was to replace the carburetor in order to get it to pass emissions. Don't know much about carbs or what what on it from the factory. Does yours have the factory (or equivalent) carb, just curious?

 

My 240 has the stock Carter YF 1-bbl carburetor.

As with most of these old 240/300s, my exhaust manifold has a crack in it where it transitions up to the bottom of the intake manifold. I do have a pair of '87-'96 4.9L (fuel injected 300) exhaust manifolds but, I haven't completely made up my mind if I'll install them or not.

For a number of years, I've had a complete fuel injected 5.0L H.O. engine, sitting on the engine stand in my shop, I pulled from a totaled '90 Mustang GT. My original plan was to make a 331 stroker out of it and put it in my '68 Mustang.

However, the '69 F100 came along in 2011 and I decided I would rather install the 5.0L engine in my truck.

Since I bought my truck though, my uncle had given me an early '70s 351W engine. I have a 5.8L GT40 EFI lower intake that the tubular GT40 upper intake, from my 5.0L engine, would bolt to.

I could retro-fit a reduced base circle roller cam in the 351W, install the EFI components on it and it would be a roller cammed fuel injected 351W.

My stock and current transmission is a C-4 automatic (non-overdriven 3-spd. transmission). I have a Ford 4R70W (electronically shifted) 4-spd. automatic overdrive transmission from a 1998 3.8L Mustang that will replace the C-4. I have a Baumann stand-alone shift controller that will handle the shifting chores of the transmission.

I much prefer EFI and overdrive transmissions to carburetion and non-overdriven transmissions.

1990 Mustang GT 5.0L H.O. fuel injected engine, 24 lb/hr Cobra fuel injectors (stock injectors were 19 lb/hr), 70mm Edelbrock throttle body, Cobra lower intake with a GT40 tubular upper intake. IF I install this engine, everything will be cleaned up and freshly painted.



The 4R70W 4-spd. overdrive transmission that will replace my C-4 3-spd. non-overdriven automatic.

 

Colorado69 Welcome to and the Bumpside Forum.

Problem is you have the smallest available engine for that big azz 3/4 ton truck. You can put a Petronix ign set in, do some tweaking on the carb. but it is gonna still be wimpy.

When getting on the road run it on up to about 50 in 3rd and just keep mashing on the pedal. You won't blow it up running down the road even though it may sound like it's screaming.


John

 

Also have a 240. It's rebuilt and can get up to 65 but it's screaming. Also bought a fuel injected 5.0l for truck! Can't wait for the swap!

 

What was the most challenging thing in your swap? Also have a fuel injected 5.0l but don't know what to expect during the swap.

 

I haven't installed the EFI engine or the overdrive transmission, yet. They are future projects that will eventually take the place of my 240 and C-4.

 

Don't forget the PCM, MAF sensor, and the injectors have to match. A factory PCM is of course calibrated for 19 pounders. Adding 24 pounders will either require a Programmer or a C&L MAF sensor body with a 24# tube. Unless there is a 3rd option out in the market I am unaware of.

 

I have a 73mm C&L Vortec Mass Air Meter that's calibrated to the 24 lb/hr injectors.

I also have an EEC-IV A9L processor for a 5.0L engine with a standard transmission and an A9P processor for a 5.0L engine with an automatic transmission.