I have a 1997 F350 4x4 off road with the 7.5L 460, ZF 5-speed, 3.55 ratio gears, and 32" o.d. tires. At 70mph, it is very close to 2,000rpm on the dot. The motor seems to like the lower rpm's more than it does winding out and rarely sees over 3,000-3,500rpm even getting on it. The best mileage I've gotten on a LONG stretch of good highway is 13.5, but 11.5-12mpg is more realistic. It is not a daily driver, but I do want it to last. I may put 285 series (33" o.d.) tires on in the future, but no bigger. It currently has a true 2 into 1 Hooker aerochamber muffler and 3" exhaust, air restrictor removed in intake, but no other mods. Anticipate a full Banks kit in future.

I'm considering changing the rear end ratio to a 4.10 or a 4.30. I know the 4.10 came as an option so not too worried about that and would put my rpm's around 2,400 at 70 in overdrive with the 4.30 being about 100 more. Increasing the tire size will bring it down just under 100rpm. I know the 4.30 is a very popular ratio in the V10 trucks, but that motor seems to have a wider powerband.

My question is how many cruising rpms is too many for the 460?

 

1600 to 2600 RPM is the standard towing RPM.
3000 RPM would be the max.
Have you driven with the overdrive off, just to imagine cruising at 2400 RPM ? Does 2400 seem to be a good cruising RPM for you ?

 

He has a 5-spd., so I would imagine towing in 4th at hightway speed would send his 460 screamin'.

OP: ideally, the best towing RPM would be in the RPM range where the engine makes the most torque. However in real-world applications, use the RPM range where the engine is not lugging/straining, while not overspeeding either.

 

I have a 94 F250 4x4 4.10 E4OD so can't give you exact answers.

But min general, I would say the mid 90s 460 engine likes to run between 2000 and no more than 4,000 RPM. My highway RPMs are around 2000 to 2500 if I recall.

Anything around 4000 and above just makes a lot of noise but no real additional power.

FWIW,

Jim Henderson

 

Never tow in overdrive or you will break something in the drive train, Towing is done in 4th at the most. Ideal towing RPM depends on the engine and its power bad, but with a 460 usually 2800 is the most you should turn. Find out where you engine makes Peak Torque, and run it there, that is where the engine is most efficient. One question, why the hell do all you guys want to tow at 70 mph? It is dangerous at best and stupid at the worst.

 

It looks like the thread was titled Towing RPM, but the question is cruising RPM at 70.

 

Perhaps I didnt make myself clear enough. I typically tow at 60-65 and only use overdrive if its a light load and a flat stretch. I drive/cruise at 70 or so in overdrive. Im interested in better power when towing, but not at the expense ov overly high rpms when cruising. I know 4.10 was offered from factory and I still have 32" tires for now. Will the 4.30's at 2500rpm or so be too much rpm cruising at 70 with the 32's until I go for the 285's? By calculations that should drop it by 100rpm or so.

 

With my last 390 in the old 1968 F250, basically a 390 GT with an RV cam( 256 duration and .505" lift), C6, 3.73 rear end and 235X16 tires I found that anything over 2900 RPM started a drastic decrease in fuel economy. As it happens my 1984 F250 with 460 with C6 and 4.10s has the same condition, so with the 390 60 to 63 mph was no problem (even though 55 was better than 60) whereas the 460 will not do over 58 mph without the gas gauge dropping like a stone in the lake.

Now for my rant. The only real way to know is try different speeds and you damn well do NOT have to drive the speed limit. If you insist on the speed limit then about gas mileage. You really are not interested in achieving improved mileage, because slowing down is the cheapest and best way to improve mileage.

 

I have a 89 250 with the 460 5 speed and 410's. Bought new and has been riding on 35's since the oem's wore out. I regularly tow a 5000lb boat and use 5 gear MOST time other than on hills. Dont have a tach and never missed it so not sure the RPM's. I will say this though... still have factory clutch and rear brakes with absolutely no issues.

 

I have a 1992 CC F350 4x4 with a ZF5 5 speed and 3.55 gears. I regularly tow my gooseneck horse trailer that weighs 11k fully loaded or my tow hauler that is about 8k loaded. At 65 in fourth gear I am turning 2500 70 is about 2700 and it pulls great and I never pull in overdrive. I was going to change gears when I bought the truck but decided to work on the engine instead I would wait until you install the banks kit and then decide if you still want to change gears. I have a Fipk kit, air horns removed, a bigger cam, Doug Thorley tri y headers and 3" flowmaster exhaust. When I am not pulling I can run in overdrive at 70mph turning 2000 rpm and get 14 to 14.5 I don't think I would get that with 4.10 gears. One side note for Bear I have towed my gooseneck at 70mph for thousands of miles I admit the crewcab wheel base makes a difference but if you are set up properly it isn't stupid or dangerous of course I am out in the country where there are far less idiots on the road.
jmo of course.
Richard

 

This thread reminds me of the old George Carlin bit where he says anyone going slower than you is a total idiot, anyone going faster than you is a MANIAC!!

My truck has the E4OD auto, the transmission builder says to leave it in OD unless it is hunting for a gear (shifting back and forth from 3rd to 4th) and then to take it out of OD just to reduce the annoying shifting. He said the trans can take the shifting just fine, it just gets annoying. Trans is pretty well built though, so stock transmissions might not be the same. With 4.10s and 31" tires I'm kinda between gears when towing my 8k TT. The 1-1 third spins a little fast (2400 at 60) and OD drops to about 1800 or so at 60. I'm looking for more torque now (I've got ported and milled heads, a cam and plan to replace the pistons and zero deck the block whenever I can live without the truck for 3-4 weeks) but if that doesn't do the trick then I'm thinking of some taller tires to drop the RPM in 3rd. The sweet spot now is either 55-58 in 3rd or 65-68 in OD, I'd like it to be happy at 60-65 although my rig is very stable at 70+. And like the Bear said, MPGs drop fast over 60..

 

i have a v 10 with 430 gears and i am very satified with it[bull dog 5 speed] i also have a 87 460 with 3.54 dana 80[i know they tell you it's a 3.55 but it isn't,it's a 3.54]]460's like 3000 rpm the only reson it has problems with higher rpm's is because of the poor cam profiles that ford put in them... 2800 rpm is the optimum rpm for carburated engines that are stock.. if you want effortless towing-no down shifting-cruise control driving go to the 430's... afterall if you wanted gas mileage you would be driving a toyota

 

are you sure that they are 355's i did not think that was an option???

 

It's a torque motor not an RPM motor. The cam works great for a torque motor. If your are stupid enough to want high RPM with a 460 put a CJ or SCJ cam, heads and intake on it. Better yet, if you want high RPM go get a small block chevy.

 

hey bear iwas just trying to help..don't be mad at me...oh and by the way the 460 was not a toque motor it came about because ford wanted a screamer to race in nascar [hemi 429] they stroked the motor and named it the 385 series because of the stroke so they could put it in the lincolns and large pick-ups of the period[70's] the head variations were for police cars and other mid size pony cars up untill about 1979.. they also used this motor for jet boats and industrial equiptment,,but after 1971 there was no further factory upgrading to the motor..only ford svo racing ever made anything that could be racing parts,,and you can buy them at ford racing.com.. the 428 fe engine made more low end torque than the 460...but all is not lost ford in their wisfom made the 460 the most buildable engine in the world and eagle products has the parts you need to have anything you want.. so try to be nice to me i cant help hw i was raised..