I have a bunch of questions here:
I found an 87 F350 4x4 for sale that doesn't have a price listed on it and was wondering what would be a reasonable price for it. It has the 6.9 motor, 5 speed manual tranny, Kingpin 60Front, Dually Sterling rear, it's rust-free, and the interior is spotless. It was a work truck that I have seen driven around town by a construction crew. If the mileage is decent, what would you guys pay for it? Also, I know the 5 speed in the truck is a ZF tranny, but what model is it and what is the ratios in it?
I want to tow at most, 10,000lbs with the truck if I buy it and would also like to know if the 6.9 would handle pulling that kind of load up long steep hills. If I start at the bottom of the hill at 55mph, would I end up at the top at only 35mph with that motor?

 

As far as worth is concerned- I have no idea. As far as the 6.9's pulling power-I think its great. Its definately not gonna pull like a new truck with a turbo, but mine has the c6 and geared low so it goes over hills okay. I have never towed anything heavy, but I've heard that it does fairly well on pulling grades. I would check what gears it has. Low is great for towing and 4x4'n, but hard on your mpg's. Hope it goes well with the purchasing.

 

First off, you have what might very well be the single best year for the IDI with every desirable option already on it. Indeed, it might be one of the all time best years for any light F series truck.

You have the last year of the 6.9, so it should have the better rocker arms, fuel filter/water separator, and better glow plug system. 1987 was the only year you can find these 6.9L IDIs.

You have the first year the 5 spreed was optional and it seem this one has it so fuel economy won't be limited to the low teens, (later had the 7.3 engine that can't be rebuilt as reliably, and earlier didn't have overdrive 5 speeds). The dual mass flywheel can be problematic, but it can be replaced with an aftermarket to give similar reliability to the older 4 speed manual (~$500 for all new parts).

And you have the much sought after dana 60 king pin front axle.

Rust free is always a good thing.

For towing 10 000lbs, it will do it, but will be slow on the hills or into a head wind. Turbocharging can fix this, but if you can be satisfied with towing that kind of weight at 55 MPH instead of 75, you will be happy.

Its hard to say what I would offer without seeing it, but if nothing is wrong with it, then I would go as high as $4000, maybe higher if it was really nice and had low miles. Prices also vary by region, so look at a few other IDIs in the area to get an idea for what would be palatable for the seller.

 

Does anyone know the gearing for the 5 speed transmission?

 

There were two ZF-5s the 42 and the 47.
Somebody will come by with the info, I've seen it on here before..

The 47s are stronger, I have 2 ZF-5s and they are both the 42s.....just my luck.......infact my 4wd version even has the crappier slip-yoke instead of the fixed-yoke which is a lot better..

 

On the drivers side of the transmission, about 1/2 way up the side and near the shifter location for front to back, there will be an ID tag with the gearing info.

The ZF had three different gear ratios possible in two different models, so it could be any of four different ratios.

Overdrive is either .76 or .77 in all of them.
Low and reverse is where the biggest variation is.

Low gear ratios possible are 4.14, 4.65, 5.08 and 5.72.

 

After closer investigation I discovered that their is something shady about the truck. The truck has no id tag inside the sticker panel because it was repainted. Also, the registration stick says 1987 but the 6.9 motor tag says 1983. So either the original motor died and they put in an 83 and just painted the truck or it was originally a 1983 truck that was wrecked. Then someone bought a 1987 donor truck and put that body on it and just registered it as the new truck. Either way, I don't think I'm going to buy it now. I think the 6.9 is a great motor but I really just wanted to have a truck with the ZF5 in it. My current truck has only the three speed C6 in it and it kills me on gas with the 460.

 

If the swap was well done, is that such big a reason to not buy it?
BTW, swaping your c6 to a zf 5 speed can be done.

 

As for towing power it will do fine with 10,000 pounds. We have a 1987 Ford E350 26 ft. motorhome that weights 10,400 pounds and we did the Canadian Rocky's with it. Starting at the bottom of a big hill at 60 MPH by the time you get up you'll be around 40-45 ish, and it's stock with a C6 automatic. So you with a 5 speed you should not have any problems! No need to waste money in putting in a Turbo, unless your always in a hurry....

 

The '83 motor has none of the uprades that the late '85 had or the valvetrain of the '87.
'83 was the worst year of the IDI anyway. First and worst.

 

I disagree, I own a 6.9 NA and a '94 IDI Turbo and that 6.9's gettin' a turbo for SURE. The only down side is the cost of the turbo and they can be had quite reasonably used.
The difference with the turbo on is HUGE!
As far as diesels go: TURBO TURBO TURBO TURBO TURBO TURBO!!!!!!!!!!!

 

As soon as I can afford it, mine's gettin' a turbo! I agree with Dodge/Cummins: its all about the turbo if you wanna tow. Although, is it true that a turbo puts more wear and tear on the motor? Can a non-turbo 6.9 last longer?

 

Haha well my "turbo" on my 6.9 is a 7.3 IP lol, acually made a fair difference. But NEVER will I put a Turbo on my 6.9 and 1990 7.3 I hate the Whistle a turbo makes! And plus i'm all about keeping everything as original as possible so me putting a turbo would kill the originallity. But yes lol I do agree a turbo makes a BIG difference, i've driven a 2001 7.3 Powerstroke.

 

In my experience you're lucky you drove a 2001 PS because the '94-'97 PSs are kind of a dog stock.
My buddy's '01 PS has a "chip" but it is WAY quicker than my '97.
My '94 IDI turbo is pretty much stock and suprisingly it's not too far behind the '01 and will blow the doors off of my '97 PS.

BTW your motorhome must be kinda rare. I've been looking for a later body style 7.3L IDI conversion van and they're hard to find, most are work vans. I might have to settle for a PS.

 

what makes it the worst?
I have one and it has never let me down.