Hi Ford guys, I am new here and looking for some advice about how to modify my 83 F-150 6cyl 4.9 so that I can afford to tow my 22' travel trailer without having to fill both tanks (gas) for every trip. I am not required to have all the emission stuff anymore or subject to yearly inspections because the truck is 36 yrs old, so this is what I have done so far, I removed the air injection pump and all the lines to each exhaust manifold port, removed the EGR valve and plugged the manifold holes, removed the Catalytic converter and replaced it with a glass pac, replaced the feedback carburetor (1bbl) with a aftermarket carburetor (Partol 1 bbl), removed the MSU computer and the ignition module for the Ford Duraspark ignition and replaced it with a distributor from "A Performance" that is Ford on the bottom so that it fits the engine and it is Chevy HEI on top with the distributor cap and coil mounted on top of the cap, and new 8mm wires. This setup has one 12v ignition wire (that eliminates the old Ford Duraspark ignition module and MSU computer), I also replaced the old BSF 42 spark plugs with Autolite AP 45 platinum plugs but I don't know if they are better or not. The truck runs way better than it did before all these changes but I haven't towed the trailer yet, I am getting about 15 mpg now (used to get about 12 mpg). The truck is a 4 speed manual with 3.08 differential and 2.25 X15 tires, I try to keep it under 3k on the highway because the old six doesn't like high rpm's too much (165k miles on the odometer). I replaced the lifters and oil pump and camshaft gear 5 yrs ago, and put in an oversize radiator from a 460 Ford truck. I would greatly appreciate any wisdom from any of you guys who can advise me further (especially about the spark plugs) as I have done a lot of stuff but I have exhausted my knowledge now and I'm not sure if everything that I have done is all good or not, Thank you

 

Moved to forum relating to your engine.

 

Thanks George for putting my post in the right place, maybe I will get some advice that will be helpful, Steve

 

Welcome to FTE.
As to not filling both tanks and pulling a 22' trailer can happen if only going a short distance of say 100 miles maybe.
Now if you are going 500 miles pulling the same trailer and not wanting to fill both tanks you will just have to make more stops to fill that 1 tank is all LOL
Duel tanks just lets you drive farther before you need to stop for gas.
Also know that pulling that heavy box behind you is going to make the MPG go down.
BTW 15 MPG is not bad empty in my book.

Just because you have a six does not make it get better MPG loaded or not.
Maybe sometimes even worst MPG because you have to work that smaller motor harder, more throttle, to do the same work as say a big 460 v8.
Also know that six is not a power house, it will get the job done but just not fast.

You also did not say what 4sp transmission you have?
Granny first gear or is it the SROD that is a 3sp with 4th as an over drive?

This can also make a difference on what load it can handle.
I hear the SROD does not have a good first gear for starting from a stop unloaded so with a trailer you will need to slip (wear) the clutch.
Also with the OD and 3.08 rear gear may be to low in the power band of the six to use OD and may only be able to stay in 3rd gear.
The granny gear transmission are better for getting loads moving from a stop but don't have over drive, 4th is 1:1, but with the 3.08 rear gear may put you in the power band.

I have a 81 F100 flare side with a 300 six & granny 4sp & 2.75 rear gear.
I have all the vacuum lines not needed removed, no EGR stock 1v carb, EFI exh. manifolds and DSII IGN
I just got it on the road and no tuning yet and only getting about 12 MPG high way (65-70 MPH) and back roads (stop lights & 45 MPH) I would be happy with 15.
I have not had a heavy load or pulled my car trailer yet but I don't think I would have issues with either just have to do it slow because of the six.

BTW I added duel tanks to my truck, not a factory option on flare sides, and so far happy I did so as I can drive farther between fill ups.
Dave ----

 

Here's a good thread discussing fuel mileage. https://www.ford-trucks.com/forums/1...-9l-300-a.html

 

Thanks Dave for all the great info, I think that my tranny is the T18 it is the one with granny gear that has no syncro. In the past we have had to go down to 2nd gear at times on the mountain roads here in Oregon and I do think that the 4th gear is just 1:1 because at 65 mph the old six sounds like it wants to jump right out of the truck, I just installed a tach so I am hoping to cruise without pushing the old girl too hard.
I'm sure that you are correct about the mileage, 15mpg is much better than it used to get without the trailer so we will see what happens this summer when we tow it somewhere. I am hoping that since all the emission stuff is gone now that it will do a little better than it used to, the engine compartment is way cleaner now without all the wires and vacuum lines in the way, and it is running about 4 degrees more advance than before which makes the idle and accelerate response much better.
Does your 81 have a feedback carb? I replaced this one because I could never get it to idle smoothly and it had a flat spot on accelerating under load, I'm hoping that will be gone when we pull the trailer.
Again, thanks for the info it is much appreciated, Steve

 

It does sound like you have the T18 like my truck has.
It a work horse of a transmission like the other granny 4sp's as it is used in much larger trucks.

If you are going to be pulling that trailer a lot with that truck you may want to look into a rear gear change to say a 3.50 or 3.73.
It will bring the RPM up some in any given speed and may limit top speed but put you in a better power range area.
Then you have over drive units you could bolt on.
I like this one and when I come into some money may get it and the price is not too bad either http://www.advanceadapters.com/categ...-splitter/236/
What is nice is you can split all the gears. When you hit a hill and you are in OD 4th just go into 4th direct. And where 3rd direct is too much go to 3rd OD.
Maybe that hill you were in 2nd gear you could have used the 2nd OD and kept the RPM low but still been in the power band.

Then you have http://www.gearvendors.com/trucks-towing.html this only works if going over I think its 15 MPH so that would be 2 gear on up, the AA unit you can split ALL gears.
It is a lot more money and does not have a shift lever, works by button & speed. Little easier to install but cant be used with 4x4.

Going with the OD units you can change the rear gear to that 3.73 for good starts from a stop but when in 4th OD could be lower RPM than what you are at now.
Would need to run some numbers to tell for sure.
Both depend on what you are looking for and how deep the pockets are LOL

No feed back system on the 81's, think started with the 83 model year IIRC just the way I like it
Dave ----

 

Hi Dave,
Hey thank you, lots of great info I didn't know that there was an OD available for this truck, if I had known 25 yrs ago it would have been a great option for running without the trailer. I'm too old now (72) to change trannys under the truck and I probably won't be running this for too many more yrs so I'll stay with just changing the easy stuff like the dist. and carb and be happy with it. What do you think that I should run the rpms at on the highway while pulling the trailer? I had a 61 F-100 yrs ago with a 292 v8 and auto tranny that ran right at 3k at 65 mph but it had taller gears in the differential. That is why I was shooting for about 3k for the 83, the trailer weight is about 6400 lbs loaded.
Great talkin to you I'm learning lots, Steve

 

Steve, I cant say what RPM to shoot for when pulling the trailer as I just don't know.
I have not pulled anything with mine yet, just on the road after a 4 year cab off frame rebuild and I never drove it before I pulled it apart,
Rolled if off the trailer made sure motor ran good and pulled it all apart for the rebuild.
I also have not put a lot of miles on it since back on the road in November but can say it does pretty good at 65 to 75 MPH with the RPM below 3k IIRC.
I have been trying to keep it to under 65 MPH in hopes of better MPG than the 12 I got so far and that is empty!

On some "hills" when pulling a heavy load you may need to drop down to 2nd gear and just go slow like the big rigs do.
There was 1 time pulling up the DE gap from PA I had to drop my 02 Durango (360 EFI / auto OD w/3.92 rear gear) to 2nd gear and follow the trucks to the top, it just happens some times.

I would say let the truck do it's thing, all be it slowly and enjoy the slow ride as life goes by so fast now days.
Dave ----

 

Hi Dave, thanks for the info, it has been raining like crazy here so I haven't got to work on the old truck for a week. It ran out of gas and it won't pull it out of either tank so I think that I may have a split gas line on the top of one of the tanks, but it is too wet to look, I put a one gallon jug on the fuel line at the drivers side fender well and it ran awesome, my next plan is to try to adjust the timing and idle with a vacuum gauge for fine tuning, so far it is running better than it has in years though with the new ignition and carb and zero smog stuff, I wish that I had done it years ago!
Hope your project is going well it sounds like you really start from scratch on your projects, I don't think that I have that much time left at 72 so I try to cut corners a little.
Have a great day, it's good talking to you and I agree with your advice about downshifting and not trying to push too hard on the hills.
Steve

 

I will be 60 come April and not as fast as I use to be also LOL
Yea my project started to get the truck road ready just to take trash to the dump weekly and got out of hand and turned into a 4 year cab off frame rebuild.
CL ad before I bought it




After





Some seeing the pictures might get a kick needed to start on their projects.
I feel for you and not being able to work on the truck because of the weather.
Does it ever stop raining out there LOL A few years ago the wife and I took vacation out there and for the full week we only had 1 day it was gloomy and that was the day we were leaving.
I am lucky I have "my garage" for working on my projects.


Good luck on your project
Dave ----

 

Hi Dave,
Wow you did a lot of work on that one, it looks great, if mine turns out well I will probably fix the minor dents and paint it also as the original paint is from "83" and so it's not real pretty any longer.
Still raining here so I just stay in the house a lot,(Iv'e had the same warden for over 52 yrs and she doesn't let me out much when its cold).
Great pics of the old truck, you made it look new again!
Steve

 

Thanks on the truck.
My keeper of 21 years did not like me getting the truck and even more so when I started to take it all apart.
Once she saw paint on it 4 years later, she told me she liked it then LOL

Last winter I picked up a 75,000 - 125,000 BTU propane heater for my garage. It works great heating the garage for not being insulated.

As for the cold the wife does not like me out in it either and wished I did not have to go out and work in it.
When it gets cold out I drive a LP tank trailer truck. So far this winter it has been pretty warm for the most part, no snow or ice (yet and hope not).
When heading out the door at 12am it is cold enough to form ice on standing water some mornings.

I hope the rain stops so you can get out to tinker on the truck.
Dave ----

 

Might think of upgrading your brakes, too... it's nice to start 'em rolling but in an emergency it's even nicer to stop 'em!

 

I dont see any thing wrong with the factory brakes if they are kept up.
Mine are all new from master / booster, everything in the drums (wheel cly, springs, shoes, ebrake cables, drums).
Upfront the rotors were still good but new calipers & pads were used after re-packing the bearings and new seals and all 3 rubber hoses were replaced too.

I don't get were people say "Oh 4 wheel drum brakes are no good and you need to upgrade to 4 wheel disc"?
Again if they are kept in good shape they are just as good in my book.
Heck I got a factory v8 small body car with 4 wheel non power drum brakes and it stops great.
It will lock up all 4 and stop straight if you want them to, I don't see going front disc would help that car any and I had the same car with a straight six and front disc so I know.

Now when I start pulling my car trailer I will have an electric brake controller installed in the truck as the trailer has electric brakes.
I still need to get & install the controller and wire the 7 pin connector I have already mounted. I also have the trailer light Tee in to the tail light harness and flat 4 installed that will go into the 7 pin connector.
Hitch & connector not wired yet.

Dave ----