Okay, so I have a 69 F250.

Currently I have a 390 in it. I'm making plans for before it dies. I'd like the engine and transmission I plan on implanting, sitting in my garage ready to go.

So I was wondering about a 300 i6. Obviously I'm no idiot. Two less cylinders and 90 less cubic inches equals a loss in capability. However the low end torque, ease of transplant, and reliability of the engine has peeked my interest. Not to mention I love big old iron straight sixes. Basically my question is, what could I bumper pull and fifth wheel tow with that engine? I plan on going to a manual trans after doing the swap, and I have 4.10 rear end. Currently I've pulled 8-9k range with ease. I'd just like to see how bad this engine will drop my capability.

 

The 300 will pull that. And if you are willing to do a few mods to the engine it will do it even easier.


Check out this video on Youtube. It's a guy that did a similar swap and it shows a little load that he hauls with it.

 

That's impressive. I've always been a fan of six cylinder engines. My first truck was a 70's Ram 200 with a 225 Slant Six. Ever since, I've loved em. Good low torque. Reliable. Low maintenance. I've always wanted to see what the old 300 could do. Thanks for the video my man.

 

Here is my experience towing with my '87 300. I pull my car trailer with my Dodge 488ci V-10, and I can't tell it's back there empty, and it will eat up a hill loaded.

The fuel pump went out on the Dodge one day. I hooked the trailer to my Ford 4.9 to get it. It's a NP435 4 speed with 3.08 rears. I had a hard time going up hills empty. With the regular cab Dodge 2500 on the trailer, I had a hard time getting up to speed, and had to drop at least one gear on every small hill, and down to second on big hills.

As the saying goes, there is no replacement for displacement. I really wish my 4.9 could handle the trailer loaded so I wouldn't need two trucks, but the Dodge will snap your neck backwards on take off loaded, where the Ford won't with no trailer hooked to it.

 

If your 300 is that gutless you need to figure out what's wrong with it. I've hauled a whole lot of vehicles with 300 powered trucks and vans. I've hauled a couple different grain trucks with on my 20 foot car trailer. And they weighed a lot more then your dodge.

It's no big surprise that a truck with almost a 200 cubic inch larger engine will out perform a 300. The 3.08's aren't helping any but I've towed with them before too. But I guess it was a good thing you had the Ford to haul your dodge when it broke down. j/k

 

Yeah, with that high of gearing, I'd imagine an old straight six have difficulty for sure. I'm fairly certain my old 390 would too. It'd be able to pull still, but the gearing would definitely hurt its ability to do so. If you don't mind me asking, how heavy is your trailer empty and loaded up?

You may want to consider going to much lower gearing. Then wala, one truck wonder!

See the old 300s went in UPS trucks, and throughout the seventies they went in dump trucks with 30,000 GVWR. My truck only weighs 4,xxx. So I should have plenty of extra loading to do, with proper gearing and such. Obviously you own one, I've never touched one, so I can't tell you how to put gas into it. Hahaha.

 

Depends on how much of a hurry you're in when you're towing. On a highway where the speed limit is 75 and everyone drives 80 you'll be a chicane.

 

https://fordsix.com/viewtopic.php?f=...2820cd3b0ed41f

There is my experience loaded and towing.

 

Don't know if you are talking to me or Yardbird about the trailer weight question. I've got 2 20' car trailers. The lighter one is 2,200 lbs empty. And I believe the heavier one is around 3,000 pounds.


Your truck's 4.10 gears should be more then good enough. But I would say the manual swap will be a must do. The C6 is just too much of a power robber. It will make towing with the 300 miserable. You will have to work the 300 harder then you do the 390 to do the same job. But it will do the job. And the more mods you do to the engine the easier it'll do the job.

 

Yeah. I plan to find a good 5 or 6 speed trans to hook up too it. I'll probably be stuck with a 5 speed, but that'll work. I'm actually pretty excited to do it. I think imma buy a 300 build her up and put it in regardless if the 390 is dead or not. If it isn't dead, I'll just rebuild it too, then mothball it and save it for a rainy day.