I had a stock 92 4x4 F-250 extended cab (5-speed) with the 5.8 EFI (351). I looked up the HP and torque rating and I think it is 200 HP @ 3800 RPM and 300 LBS @ 2800 RPM. Is that about right?

I now have a F-150 4x4 (auto) with the 4.6 rated at 231 HP @ 4750 and 293 LBS at 3500 RPM. Both had tow packages.

Now, that old F-250 would pull a house. I know the RPM curves are a little better for it as well. But for basic highway boat and medium trailer towing (4500 lbs and less), will the F-150 with only 7 less LBS torque and a better top end HP rating tow about the same or better?

 

Well, it's not going to pull as nicely from a stop as the old 351w. You probably had a lot shorter gears on the F250 than your F150 as well, and if this is the case, you will also notice that it's harder to get everything moving.

 

The 4.6 power curve is very narrow compared to the wide, flat curve for the 5.8. The 4.6 may make more power in a very narrow (and quite high RPM range; it may even make nearly as much torque but it's only going to do it in a narrow and quite high range. The 5.8 will pull hard at every RPM.

The 4.6 is basically a passenger car engine stuffed into a truck for people who use their trucks to haul groceries. The 5.8 is a truck engine.

 

I understand the curve difference. Believe me, that F-250 would pull mountains on the low end and it would pull a long 5th wheel camper to Alaska and back every summer no problem. Of course it nearly ran OPEC out of crude, but that's another story.

My future needs are for a bass boat. Three years back, I drove a friends truck with the 4.6 towing a big glass bass boat that weighed 5000 LBS and it seemed more than up to the task, but that was only for a twenty miles or so. I will have a 3500-4000 LB boat. Wont the F-150's HP and Torque ranges be fine for normal HWY driving there?

 

Yeh, it will be fine. Its just your rear end gears that will limit acceleration pulling the load. I have heard that manually shifting your tranny when its in the power band works pretty good, but I would NOT recommend it though.

But I DO recommend that you not tow in overdrive. That willl shorten your trans life alot.

Happy bassin,

 

Yeah I stay out of OD when driving around town, even with no load. I dont like all the additional shifting. I assume on a flat highway, the OD could be used when towing this type of load as long as the thing isn't shearching for gears?

 

Around town your trans will not shift into OD anyway so it really doesn't matter were you place the shifter. They are designed to go into OD at a specific speed/acceleration load. My shop truck has a 4.6 auto, and no matter how slow you accelerate, it will not go into OD unless you hit 43mph or higher.

If also wouldn't recommend a forced downshift when towing. With all the added weight it would probably be best to let it shift itself.

 

My 03 will not shift into into final O/D until about 43 as you said. But, engaging the O/D off button changes the shift pattern and RPMs at lower speeds as well. At least it sure sounds, feels, and pulls different.

 

Green 67, I would not tow in OD at all with any thing over 1/3 of the rated tow capacity of the truck. The trans will generate more heat and shorten its life. Its not the shifting that wears a tranny out, its slipping the clutch plates while running on the highway. That creates heat, breaks down the fluid, increases wear, shortens trans life! If the engine is making more torque than the clutches can take, they slip. With the torque converter locked up in OD, the extra torque from the engine goes to the tranny clutches (the only place that is not a solid connection at this point) and too heavy of a load will place a higher requirement of torque than the tranny can deliver in OD. Create heats from slipping the clutches, early tranny failure!

 

I know what you are saying. My 95 351 will totally outpull, outrun, outmud, out whatever, our 97 F150 4.6 4x4.

 

well, as far as the towing in overdrive thing goes, my 93 bronco with 351 and E40D (both original and never been apart), has done lots of towing of a 26' powerboat, and enclosed snowmobile trailers in the winter time. When towing on level grades, i've always used overdrive, just goin down the highway at a steady speed, 70-75 in many cases, if not higher, and when there are hills in the area, then i lock it out of OD, to prevent the harsh downshifts out of OD when pullin a load. Well, that's over 120,000 miles now. The same technique goes for my grandpa's 2000 f150 4x4 with 4r70w trans and over 100,000 miles on the 5.4L and the trans, pullin the same amount of weight. just gotta use your head when you tow using OD, if it's too much of a load, or you gotta go up and down hills, just lock if out of OD, otherwise there is no problem. Just had to add my two cents, as people are always saying a BIG NO to towing AT ALL in OD. If it matters i'm a mechanic at a dodge dealer, and my grandpa owned a shop for 40 years, interesting how we've never had probs.